feat(ui): filter already-added chars from participant dropdown

Character dropdown in add-participant picker excluded characters already
in the encounter. Prevents dup-add at the source — user can only select
chars not yet participating.

.githooks/pre-push

@@ -0,0 +1,5 @@
+#!/bin/sh
+# pre-push: run test suites before push. Skip with --no-verify.
+echo "[pre-push] running tests..."
+npm run test:all || { echo "[pre-push] tests failed. push aborted. (skip: git push --no-verify)"; exit 1; }
+exit 0

.gitignore

@@ -1,4 +1,3 @@
-# .gitignore
 node_modules
 build
 dist
@@ -6,4 +5,12 @@ dist
 .env.local
 .env.development.local
 .env.test.local
-.env.production.local
+.env.production.local
+*.log
+data/*.sqlite
+data/*.sqlite-*
+server/data/*.sqlite
+server/data/*.sqlite-*
+/data
+/scratch
+tmp/

CLAUDE.md

@@ -0,0 +1,78 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Commands
+
+```bash
+npm start          # Dev server at http://localhost:3000
+npm run build      # Production build
+npm test           # Run tests (no test files currently exist)
+```
+
+Docker:
+```bash
+docker build -t ttrpg-initiative-tracker .
+docker run -p 8080:80 --rm --name ttrpg-tracker-app ttrpg-initiative-tracker
+```
+
+The Dockerfile uses `NODE_OPTIONS=--openssl-legacy-provider npm run build` to work around an OpenSSL compatibility issue between Node 18 and react-scripts 5.
+
+## Architecture
+
+Single-page React app (Create React App) for DMs to manage TTRPG combat encounters with a real-time player display. The entire application — all components, hooks, Firebase init, and routing — lives in **`src/App.js`** (~2500 lines).
+
+**Key dependencies:** React 18, Firebase SDK v10 (Firestore + anonymous auth), Tailwind CSS v3, lucide-react icons.
+
+### Two App Modes (query-param routing)
+
+- Default URL → `AdminView`: full DM interface (campaign/encounter/participant management)
+- `?playerView=true` or `/display` → `DisplayView`: read-only player-facing view for a second monitor
+
+### Firebase / Firestore
+
+All app state lives in Firestore under `artifacts/{APP_ID}/public/data/`:
+- `campaigns/` — campaign documents
+- `campaigns/{id}/encounters/` — sub-collections with a `participants` array per encounter
+- `activeDisplay/status` — single doc controlling what the player display shows
+
+`APP_ID` defaults to `"ttrpg-initiative-tracker-default"` and can be overridden via `REACT_APP_TRACKER_APP_ID`.
+
+All users authenticate anonymously (Firebase Anonymous Auth). If `window.__initial_auth_token` is set, a custom token is used instead.
+
+Real-time updates use two custom hooks in App.js: `useFirestoreDocument(docPath)` and `useFirestoreCollection(collectionPath)`, both backed by `onSnapshot`.
+
+### App.js Sections (in order)
+
+1. Constants — `APP_VERSION`, `CONDITIONS` array, defaults
+2. Firebase config — reads `REACT_APP_FIREBASE_*` env vars
+3. Firestore path helpers — `getPath` object
+4. Utility functions — `generateId()`, `rollD20()`, sort helpers
+5. Custom hooks — `useFirestoreDocument`, `useFirestoreCollection`
+6. Reusable UI — `Modal`, `ConfirmationModal`, `LoadingSpinner`, `ErrorDisplay`
+7. Feature components — forms, managers, controls (see below)
+8. `AdminView` (~line 1942) — root DM component
+9. `DisplayView` (~line 2186) — root player component
+10. `App` (~line 2426) — auth + routing
+
+Major feature components: `CreateCampaignForm`, `CreateEncounterForm`, `EditParticipantModal`, `CharacterManager`, `ParticipantManager`, `InitiativeControls`, `EncounterManager`.
+
+### Styling
+
+Tailwind CSS with two custom font families configured in `tailwind.config.js`:
+- `font-cinzel` — Cinzel (serif, used for headings)
+- `font-garamond` — Alegreya Sans (default body font)
+
+### Environment Variables
+
+Copy `env.example` to `.env.local` and fill in Firebase credentials:
+
+```
+REACT_APP_FIREBASE_API_KEY
+REACT_APP_FIREBASE_AUTH_DOMAIN
+REACT_APP_FIREBASE_PROJECT_ID
+REACT_APP_FIREBASE_STORAGE_BUCKET
+REACT_APP_FIREBASE_MESSAGING_SENDER_ID
+REACT_APP_FIREBASE_APP_ID
+REACT_APP_TRACKER_APP_ID   # optional, Firestore namespace
+```

Dockerfile

@@ -7,8 +7,11 @@ LABEL stage="build-local-testing"
 
 WORKDIR /app
 
-# Copy package.json and package-lock.json (or yarn.lock)
+# Copy root package.json/lockfile plus workspace manifests so npm can
+# resolve the @ttrpg/shared and server workspace links during install.
 COPY package*.json ./
+COPY shared/package.json ./shared/
+COPY server/package.json ./server/
 
 # Install dependencies using the lock file for consistency
 RUN npm install
@@ -38,6 +41,9 @@ LABEL stage="nginx-server"
 # Copy the build output from the 'build' stage to Nginx's html directory
 COPY --from=build /app/build /usr/share/nginx/html
 
+# Replace default nginx config with one that handles SPA client-side routing
+COPY nginx-docker.conf /etc/nginx/conf.d/default.conf
+
 # Expose port 80 (Nginx default)
 EXPOSE 80
 

LICENSE

@@ -0,0 +1,437 @@
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README.md

@@ -1,66 +1,128 @@
-# TTRPG Initiative Tracker
+# TTRPG Initiative Tracker (v0.4)
 
-This application is the result of not having the exact tool I want to use, and a few sessions of [vibe-coding](https://www.youtube.com/watch?v=Tw18-4U7mts) with [Google Gemini](https://developers.google.com/gemini-code-assist/docs/overview).
+![Here it is in use](images/in_use.png)
 
-**Use at your own risk.** 
+This application is the result of not having the exact tool I want to use, and after a few sessions of [vibe-coding](https://www.youtube.com/watch?v=Tw18-4U7mts) with [Google Gemini](https://developers.google.com/gemini-code-assist/docs/overview), here it is!.
 
-A web-based application designed to help Dungeon Masters (DMs) manage and display combat initiative for tabletop role-playing games (TTRPGs). It features a DM admin interface for controlling encounters and a separate player display view suitable for an external monitor or for players to view on their own devices.
+**Use at your own risk.**
+
+A web-based application designed to help Dungeon Masters (DMs) manage and display combat initiative for tabletop role-playing games (TTRPGs). It features a DM admin interface for controlling encounters and a separate player display view suitable for an external monitor.
+
+![](images/initiative_tracker.png)
+
+Have you tried it? Got feedback or questions? Discuss here: [https://discourse.draft13.com/c/ttrpg-initiative-tracker/16](https://discourse.draft13.com/c/ttrpg-initiative-tracker/16)
+
+As of v0.4, the app can optionally run against a self-hosted backend (Node/Express/ws/SQLite, shipped as a single Docker container) instead of Firebase — useful if you'd rather not depend on a Google account. Firebase remains the default; see [Self-Hosted Backend (Optional)](#self-hosted-backend-optional) below.
 
 ## Features
 
-![DM View](images/dm_view.png)
+![DM View.](images/dm_view.png)
 
-* **Campaign Management:** Create campaigns to organize your game sessions.
-* **Character Management:** Add and manage characters (player characters) within each campaign.
+* **Campaign Management:**
+    * Create campaigns to organize game sessions.
+    * Option to set a custom background image URL for the player display on a per-campaign basis.
+    * Campaign cards display the number of characters and encounters.
+* **Character Management:**
+    * Add and manage characters (player characters) within each campaign.
+    * Set default Max HP and default Initiative Modifier for each campaign character.
+    * The character list is collapsible to save screen space.
 * **Encounter Management:**
     * Create multiple encounters per campaign.
-    * Add characters and monsters to encounters with initiative scores and hit points.
-    * DM controls to start, advance turns, and end encounters.
+    * Add characters from the campaign roster (with auto-rolled initiative based on their modifier and HP pre-filled from campaign defaults) or add custom monsters.
+    * Monsters have an editable default initiative modifier (pre-filled at +2) and can be marked as NPCs.
+    * "Add All Campaign Characters" button for quickly populating encounters with initiative rolls.
+    * DM controls to start, pause/resume, advance turns, and end encounters.
+    * Visual feedback for rolled initiative when adding individual participants.
+    * Participants can be added mid-combat while the encounter is paused; the turn order recalculates on resume.
+* **HP Tracking:**
+    * Apply damage or healing to any participant during combat directly from the DM view.
+    * When a participant reaches 0 HP they are automatically marked inactive and shown with a skull (☠️) icon.
+    * Healing a dead participant above 0 HP revives them and reactivates them in the turn order.
+* **Death Save Tracking:**
+    * When a player character reaches 0 HP, three death save checkboxes appear in the DM view.
+    * Marking the third death save triggers a dissolve animation on the player display, then removes the participant from the encounter.
+* **Conditions:**
+    * Apply any of 22 conditions to a participant, including all standard D&D conditions plus several extras: Alchemist Fire 🔥, Bardic Inspiration 🎵, Blinded 🙈, Charmed 💘, Deafened 🔇, Exhaustion 😴, Frightened 😱, Grappled 🤜, Grazed 🩹, Incapacitated 💫, Invisible 👻, Paralyzed ⚡, Petrified 🗿, Poisoned 🤢, Prone ⬇️, Restrained 🕸️, Sapped 🔨, Shield 🛡️, Slowed 🐌, Stunned 💥, Unconscious 💤, Vexed 🎯.
+    * Active conditions are shown as emoji badges on both the DM view and the player display.
+    * Conditions can be toggled directly from the badge or from an expandable condition picker per participant.
 * **Player Display:**
-    * A clean interface showing the current initiative order and participant HP (monster HP totals are hidden, only the bar is shown).
-    * Option to set a custom background image URL for the player display on a per-campaign basis.
-    * DM can activate/deactivate encounters for the player display.
-    * Player display can be opened in a separate window.
-* **Real-time Updates:** Uses Firebase Firestore for real-time synchronization between DM actions and the player display.
-* **Initiative Tie-Breaking:** DMs can drag-and-drop participants with tied initiative scores (before an encounter starts) to set a manual order.
-* **Responsive Design:** Styled with Tailwind CSS for usability across different screen sizes.
+    * A clean interface showing the current initiative order, round number, participant HP, and current turn.
+    * HP bars use color-coded thresholds: green (above half), yellow (quarter to half), red (below quarter), dark red (dead).
+    * Monster and NPC HP totals are hidden; only the color-coded bar is shown.
+    * Player character HP can be hidden from the player display via a toggle in the DM's initiative controls ("Hide player HP"). When enabled, only the color-coded bar is shown for characters as well.
+    * Active conditions are displayed as emoji badges on each participant's card.
+    * Inactive participants (and dead ones) are greyed out with a grayscale filter.
+    * Inactive monsters (e.g. pre-staged or summoned reserves) are hidden from the player display entirely; inactive player characters still appear greyed out.
+    * The current participant's card auto-scrolls into view when the turn advances.
+    * NPCs are visually distinct from hostile monsters, which are distinct from player characters.
+    * Displays a custom campaign background image if one is set.
+    * Shows a "Game Session Paused" message when no encounter is active, or "(Combat Paused)" when the DM pauses a running encounter.
+    * Player display is opened in a separate window via the "Open Player Window" button in the DM's header.
+    * A **fullscreen button** (top-right corner) toggles the browser into fullscreen mode — ideal for a dedicated second monitor.
+    * A **prevent sleep toggle** (moon/coffee icon, top-right corner) uses the browser Wake Lock API to keep the screen on while active.
+* **Combat Action Log:** A running log of combat events (HP changes, condition changes, turn advances, participant additions/removals, encounter starts/ends, etc.) is available at `/logs`. Entries are timestamped and tagged with the encounter name. Most entries include an **↩ Undo** button that rolls back the action in Firestore (restoring HP, conditions, turn order, etc.). Rolled-back entries are greyed out with a strikethrough. The log can be cleared in bulk from that page.
+* **Real-time Updates:** Uses Firebase Firestore for real-time synchronization between DM actions and the player display (or a self-hosted WebSocket backend, see below).
+* **Initiative Tie-Breaking:** DMs can drag-and-drop participants with tied initiative scores (before an encounter starts or while paused) to set a manual order.
+* **Responsive Design:** Styled with Tailwind CSS.
+* **Confirmation Modals:** Used for destructive actions like deleting campaigns, characters, encounters, or ending combat.
 
 ## Tech Stack
 
 * **Frontend:** React
 * **Styling:** Tailwind CSS
-* **Backend/Database:** Firebase Firestore (for real-time data)
-* **Authentication:** Firebase Anonymous Authentication
+* **Backend/Database:** Firebase Firestore (default), or a self-hosted Node/Express + `ws` + SQLite (`better-sqlite3`) backend behind Caddy (optional, see [Self-Hosted Backend](#self-hosted-backend-optional))
+* **Authentication:** Firebase Anonymous Authentication (Firebase mode only; the self-hosted backend has no auth layer — intended for trusted/local networks)
+* **Shared logic:** Turn-order state machine (`shared/`) is framework-agnostic and used by both the frontend and the self-hosted backend, covered by a Jest test suite
 
 ## App Usage Overview
 
-![Screenshots](images/header_image.png)
+![](images/running_combat.png) 
 
 The TTRPG Initiative Tracker is designed for Dungeon Masters to manage combat encounters and display the initiative order to players. Here's a typical workflow:
 
 1.  **Admin Interface (DM's View):**
-    * **Create a Campaign:** Start by creating a new campaign. You can optionally provide a URL for a custom background image that will be shown on the Player Display for this campaign.
-    * **Add Characters:** Within a campaign, add your player characters to the campaign roster.
+    * **Create a Campaign:** Start by creating a new campaign. You can optionally provide a URL for a custom background image that will be shown on the Player Display for this campaign. Campaign cards will show a preview of this background.
+    * **Add Characters:** Within a campaign, add your player characters. For each, set their name, default maximum HP, and a default initiative modifier. This section is collapsible to save screen space.
     * **Create Encounters:** For each combat scenario, create an encounter within the selected campaign.
     * **Manage Participants:**
-        * Add characters from your campaign roster and any monsters to the selected encounter.
-        * Set their initiative scores and maximum hit points.
-        * If there are ties in initiative, you can drag and drop participants (before starting the encounter) to set a specific tie-breaker order.
+        * Add characters from your campaign roster. Their Max HP will pre-fill from their campaign default, and their initiative will be automatically rolled (d20 + their default modifier).
+        * Add monsters. Provide a name, Max HP, and an initiative modifier (defaults to +2 but is editable). Mark if the monster is an "NPC" for different styling. Their initiative will be automatically rolled (d20 + specified modifier).
+        * Use the "Add All From Campaign (Roll Init)" button to quickly add all campaign characters not yet in the encounter, with their initiative rolled and HP set from defaults.
+        * If there are ties in initiative, you can drag and drop participants (before starting the encounter or while it's paused) to set a specific tie-breaker order.
     * **Control Player Display:**
-        * Use the "eyeball" icon next to an encounter to toggle it as "LIVE ON PLAYER DISPLAY". This controls what is shown on the separate Player Display window. Only one encounter can be live at a time.
-        * Click the "Open Player Window" button in the header to launch a separate, clean window for your players (ideal for an external monitor).
+        * Click the "Open Player Window" button in the header to launch a separate, clean window for your players (ideal for an external monitor). This window's content is controlled by the DM.
+        * Use the "eyeball" icon next to an encounter to toggle it as "LIVE ON PLAYER DISPLAY". This controls what is shown on the Player Display window. Only one encounter can be live at a time.
     * **Run Combat:**
-        * Once participants are added and initiative is set (including any manual tie-breaking), click "Start Encounter". This also automatically makes the encounter live on the Player Display.
-        * Use the "Next Turn" button to advance through the initiative order. The current combatant will be highlighted in both the Admin View and the Player Display.
-        * Apply damage or healing to participants directly in the Admin View during combat.
-        * Mark participants as inactive (e.g., if knocked out) using the toggle next to their name.
-        * Click "End Encounter" when combat is over. This will also deactivate it from the Player Display.
+        * Once participants are added and initiative is set, click "Start Encounter". This also automatically makes the encounter live on the Player Display.
+        * Use the "Pause" button to temporarily halt combat. While paused, you can adjust HP and re-order tied initiatives. Click "Resume" to continue.
+        * Use the "Next Turn" button (disabled when paused) to advance through the initiative order. The current combatant will be highlighted.
+        * Apply damage or healing to participants directly in the Admin View. Participants at 0 HP are automatically deactivated and marked with a skull icon. Healing them above 0 HP revives them.
+        * For player characters at 0 HP, track death saving throws using the three checkboxes that appear. Marking the third failure triggers a death animation on the player display and removes the participant.
+        * Apply or remove conditions (Blinded, Charmed, Poisoned, etc.) using the ✨ button next to each participant. Active conditions appear as emoji badges on both the DM view and the player display.
+        * Mark participants as inactive (e.g., if knocked out) using the toggle next to their name. Inactive monsters are hidden from the player display entirely, making this useful for pre-staging summoned reserves.
+        * Toggle **Hide player HP** in the initiative controls to show or hide player character HP values on the player display.
+        * Click "End Encounter" (with confirmation) when combat is over. This also deactivates it from the Player Display.
 
 2.  **Player Display Window:**
-    * This window (opened by the DM) shows a simplified view of the active encounter.
-    * It displays the initiative order, current turn, round number, and participant HP (monster HP values are hidden, only the bar is shown).
-    * If a custom background URL was set for the campaign, it will be displayed.
-    * If no encounter is active on the Player Display, it will show a "Game Session Paused" message.
+    * This window (opened by the DM via the "Open Player Window" button, or accessed directly at `/display` or `/?playerView=true`) shows a simplified, header-less view of the active encounter.
+    * It displays the initiative order, current turn, round number, and participant HP bars. Monster/NPC HP totals are hidden; only the color-coded bar is shown. Player character HP is shown numerically unless the DM has enabled "Hide player HP".
+    * HP bars are color-coded: green (above 50%), yellow (25–50%), red (below 25%), dark red (dead/0 HP).
+    * Active conditions are shown as emoji badges on each participant's card.
+    * The current participant's card automatically scrolls into view when the turn advances.
+    * NPCs are styled with a muted gray background, distinct from hostile monsters (reddish-brown) and player characters (dark blue/indigo).
+    * Dead and inactive participants are greyed out with a grayscale filter. Inactive monsters are hidden entirely.
+    * When a player character's third death save is marked, a dissolve animation plays on the display before the participant is removed.
+    * If a custom background URL was set for the campaign, it will be displayed with a semi-transparent overlay behind the participant cards.
+    * If no encounter is active on the Player Display, it shows "Game Session Paused". If the current encounter is paused by the DM, it shows "(Combat Paused)".
+    * Use the **fullscreen button** (top-right) to go fullscreen — great for a dedicated second monitor. Press Escape or click again to exit.
+    * Use the **prevent sleep toggle** (moon icon, top-right) to keep the screen awake using the browser Wake Lock API. The icon turns amber and switches to a coffee cup when active.
+
+3.  **Combat Log (`/logs`):**
+    * A dedicated page that records all significant combat events: encounter starts and ends, turn advances, HP changes, condition changes, participant additions/removals, and activation toggles.
+    * Each entry is timestamped and tagged with the encounter name for easy reference.
+    * Most entries have an **↩ Undo** button. Clicking it rolls back that specific action in Firestore — restoring HP, conditions, turn order, or participant state to what it was before. The entry is then greyed out and marked "rolled back".
+    * The log can be cleared in bulk from the page (with confirmation).
+    * Accessible via the "Logs" link in the DM header or directly at `/logs`.
 
 This flow allows the DM to prepare and run encounters efficiently while providing a clear, real-time view for the players.
 
@@ -69,128 +131,182 @@ This flow allows the DM to prepare and run encounters efficiently while providin
 ### Prerequisites
 
 * **Node.js and npm:** Ensure you have Node.js (which includes npm) installed. You can download it from [nodejs.org](https://nodejs.org/).
-* **Firebase Project:** You'll need a Firebase project with Firestore Database and Anonymous Authentication enabled.
+* **Firebase Project** (only if using the default Firebase storage mode): You'll need a Firebase project with:
+    * Firestore Database created and initialized.
+    * Anonymous Authentication enabled in the "Authentication" > "Sign-in method" tab.
 * **Git:** For cloning the repository.
 
+The project is an npm workspaces monorepo (`server/`, `shared/`, plus the CRA frontend at the root) — a single `npm install` at the repo root installs everything.
+
 ### Local Development Setup (using npm)
 
-#### **Clone the Repository:**
-```bash
-git clone <your-repository-url>
-cd ttrpg-initiative-tracker
-```
-
-#### **Create Firebase Configuration File (`.env.local`):**
-* In the root of the project, create a file named `.env.local`.
-* Add your Firebase project configuration details to this file. You can find these in your Firebase project settings (Project settings > General > Your apps > Firebase SDK snippet > Config).
-* **Important:** This `.env.local` file contains sensitive API keys and should **NOT** be committed to Git. Make sure it's listed in your `.gitignore` file.
-
-Your `.env.local` should look like this:
-```ini
-REACT_APP_FIREBASE_API_KEY="YOUR_FIREBASE_API_KEY"
-REACT_APP_FIREBASE_AUTH_DOMAIN="YOUR_FIREBASE_AUTH_DOMAIN"
-REACT_APP_FIREBASE_PROJECT_ID="YOUR_FIREBASE_PROJECT_ID"
-REACT_APP_FIREBASE_STORAGE_BUCKET="YOUR_FIREBASE_STORAGE_BUCKET"
-REACT_APP_FIREBASE_MESSAGING_SENDER_ID="YOUR_FIREBASE_MESSAGING_SENDER_ID"
-REACT_APP_FIREBASE_APP_ID="YOUR_FIREBASE_APP_ID"
-
-# Used for namespacing Firestore paths, can be any unique string for your app instance
-REACT_APP_TRACKER_APP_ID="ttrpg-initiative-tracker-dev"
-```
-*An `.env.example` file is included in the repository as a template.*
-
-#### **Install Dependencies:**
-Navigate to the project root in your terminal and run:
-```bash
-npm install
-```
-This will install all the necessary packages defined in `package.json` and create a `package-lock.json` file.
-
-#### **Set up Firestore Security Rules:**
-* Go to your Firebase project console -> Firestore Database -> Rules.
-* Use the following rules for development (allows authenticated users to read/write all data). **For production, you MUST implement more restrictive rules.**
+1.  **Clone the Repository:**
+    ```bash
+    git clone https://code.draft13.com/robert/ttrpg-initiative-tracker
+    cd ttrpg-initiative-tracker
     ```
-    rules_version = '2';
-    service cloud.firestore {
-        match /databases/{database}/documents {
-        match /{document=**} {
-            allow read, write: if request.auth != null;
-        }
-        }
-    }
+
+2.  **Create Firebase Configuration File (`.env.local`):**
+    * In the root of the project, create a file named `.env.local`.
+    * Add your Firebase project configuration details to this file. You can find these in your Firebase project settings (Project settings > General > Your apps > Firebase SDK snippet > Config).
+    * **Important:** This `.env.local` file contains sensitive API keys and should **NOT** be committed to Git. Make sure it's listed in your `.gitignore` file.
+
+    Your `.env.local` should look like this:
+    ```ini
+    REACT_APP_FIREBASE_API_KEY="YOUR_FIREBASE_API_KEY"
+    REACT_APP_FIREBASE_AUTH_DOMAIN="YOUR_FIREBASE_AUTH_DOMAIN"
+    REACT_APP_FIREBASE_PROJECT_ID="YOUR_FIREBASE_PROJECT_ID"
+    REACT_APP_FIREBASE_STORAGE_BUCKET="YOUR_FIREBASE_STORAGE_BUCKET"
+    REACT_APP_FIREBASE_MESSAGING_SENDER_ID="YOUR_FIREBASE_MESSAGING_SENDER_ID"
+    REACT_APP_FIREBASE_APP_ID="YOUR_FIREBASE_APP_ID"
+
+    # Used for namespacing Firestore paths, can be any unique string for your app instance
+    REACT_APP_TRACKER_APP_ID="ttrpg-initiative-tracker-dev"
     ```
-* Publish these rules.
+    *An `.env.example` file is included in the repository as a template.*
 
-#### **Enable Anonymous Authentication:**
-* In your Firebase project console -> Authentication -> Sign-in method.
-* Enable "Anonymous" as a sign-in provider.
+3.  **Install Dependencies:**
+    Navigate to the project root in your terminal and run:
+    ```bash
+    npm install
+    ```
+    This will install all the necessary packages defined in `package.json` and create a `package-lock.json` file.
 
-#### **Run the Development Server:**
-```bash
-npm start
-```
-This will start the React development server, usually on `http://localhost:3000`. The application will open in your default web browser.
+4.  **Set up Firestore Security Rules:**
+    * Go to your Firebase project console -> Firestore Database -> Rules.
+    * Use the following rules for development (allows authenticated users to read/write all data). **For production, you MUST implement more restrictive rules.**
+        ```
+        rules_version = '2';
+        service cloud.firestore {
+          match /databases/{database}/documents {
+            match /{document=**} {
+              allow read, write: if request.auth != null;
+            }
+          }
+        }
+        ```
+    * Publish these rules.
+
+5.  **Run the Development Server:**
+    ```bash
+    npm start
+    ```
+    This will start the React development server, usually on `http://localhost:3000`. The application will open in your default web browser.
 
 ### Deployment with Docker
 
-This project includes a `Dockerfile` to containerize the application for deployment. It uses a multi-stage build:
+There are two Docker paths, depending on which storage mode you want:
+
+* **Firebase mode (default):** the root `Dockerfile` builds a static frontend-only image, described below.
+* **Self-hosted mode:** the `docker/` directory builds a single container running the Node backend + SQLite + the frontend behind Caddy, with no Firebase dependency. See [Self-Hosted Backend (Optional)](#self-hosted-backend-optional).
+
+#### Firebase-mode image (root `Dockerfile`)
+
+This project includes a `Dockerfile` to containerize the Firebase-backed application for deployment. It uses a multi-stage build:
 * **Stage 1 (build):** Installs dependencies, copies your `.env.local` (for local testing builds), and builds the static React application using `npm run build`.
 * **Stage 2 (nginx):** Uses an Nginx server to serve the static files produced in the build stage.
 
-**1. Prerequisites for Docker:**
-* Ensure Docker Desktop (or Docker Engine on Linux) is installed and running. Download from [docker.com](https://www.docker.com/products/docker-desktop).
+1.  **Prerequisites for Docker:**
+    * Ensure Docker Desktop (or Docker Engine on Linux) is installed and running. Download from [docker.com](https://www.docker.com/products/docker-desktop).
 
-**2. Building the Docker Image (for Local Testing with `.env.local`):**
-* Make sure your `.env.local` file is present in the project root and correctly configured with your Firebase details. The `Dockerfile` is set up to copy this file as `.env` during the build for local testing.
-* **Security Warning:** The image built this way will contain your Firebase API keys from `.env.local`. **Do NOT push this specific image to a public Docker registry.** For production, environment variables should be injected by your hosting platform or CI/CD pipeline at build or runtime.
+2.  **Building the Docker Image (for Local Testing with `.env.local`):**
+    * Make sure your `.env.local` file is present in the project root and correctly configured with your Firebase details. The `Dockerfile` is set up to copy this file as `.env` during the build for local testing.
+    * **Security Warning:** The image built this way will contain your Firebase API keys from `.env.local`. **Do NOT push this specific image to a public Docker registry.** For production, environment variables should be injected by your hosting platform or CI/CD pipeline at build or runtime.
 
-To build the image, navigate to the project root and run:
+    To build the image, navigate to the project root and run:
+    ```bash
+    docker build -t ttrpg-initiative-tracker .
+    ```
+    *(You can replace `ttrpg-initiative-tracker` with your preferred image name/tag).*
 
+3.  **Running the Docker Container Locally:**
+    Once the image is built, run it:
+    ```bash
+    docker run -p 8080:80 --rm --name ttrpg-tracker-app ttrpg-initiative-tracker
+    ```
+    * `-p 8080:80`: Maps port 8080 on your host machine to port 80 inside the container (where Nginx is listening).
+    * `--rm`: Automatically removes the container when it stops.
+    * `--name ttrpg-tracker-app`: Assigns a name to the running container.
+    * `ttrpg-initiative-tracker`: The name of the image you built.
+
+    You can then access the application at `http://localhost:8080`.
+
+4.  **Production Deployment Considerations:**
+    * When deploying to a production environment (e.g., a cloud provider, your own server), you should **not** copy your `.env.local` file into the Docker image.
+    * Instead, configure the `REACT_APP_FIREBASE_...` environment variables directly in your hosting platform's settings or pass them to the Docker container at runtime (if your application is set up to read them at runtime, though Create React App bakes them in at build time).
+    * If your CI/CD pipeline builds the Docker image, ensure these environment variables are securely provided to the build environment.
+    * **Implement strict Firebase Security Rules** appropriate for a production application to protect your data.
+
+### Self-Hosted Backend (Optional)
+
+If you'd rather not depend on Firebase/Google, the app can run entirely self-hosted: a Node/Express + `ws` backend backed by SQLite, with the frontend talking to it instead of Firestore. Intended for trusted/local networks (no auth layer yet).
+
+**Quickest path — Docker Compose (single container: Caddy + Node + SQLite):**
 ```bash
-docker build -t ttrpg-initiative-tracker .
+docker compose -f docker/docker-compose.yml up --build
 ```
-*(You can replace `ttrpg-initiative-tracker` with your preferred image name/tag).*
+This serves the app at `http://localhost:8080` (override with `PORT`), proxies `/api` and `/ws` to the backend, and persists the SQLite database in a named Docker volume. Override the Firestore-style app-id namespace with `TRACKER_APP_ID` if needed.
 
-**3. Running the Docker Container Locally:**
-Once the image is built, run it:
+**Local dev (recommended):**
 ```bash
-docker run -p 8080:80 --rm --name ttrpg-tracker-app ttrpg-initiative-tracker
+npm install                # installs root, server/, and shared/ workspaces
+./scripts/dev-start.sh     # backend :4001 + frontend :3999, server mode
+./scripts/dev-stop.sh      # stop both
 ```
-* `-p 8080:80`: Maps port 8080 on your host machine to port 80 inside the container (where Nginx is listening).
-* `--rm`: Automatically removes the container when it stops.
-* `--name ttrpg-tracker-app`: Assigns a name to the running container.
-* `ttrpg-initiative-tracker`: The name of the image you built.
 
-You can then access the application at `http://localhost:8080`.
+**Manual (fallback):**
+```bash
+npm install
+npm run server:dev         # starts backend on :4001 (SQLite at data/tracker.sqlite)
 
-**4. Production Deployment Considerations:**
-    
-* When deploying to a production environment (e.g., a cloud provider, your own server), you should **not** copy your `.env.local` file into the Docker image.
-* Instead, configure the `REACT_APP_FIREBASE_...` environment variables directly in your hosting platform's settings or pass them to the Docker container at runtime (if your application is set up to read them at runtime, though Create React App bakes them in at build time).
-* If your CI/CD pipeline builds the Docker image, ensure these environment variables are securely provided to the build environment.
-* **Implement strict Firebase Security Rules** appropriate for a production application to protect your data.
+# in another terminal:
+REACT_APP_STORAGE=server \
+REACT_APP_BACKEND_URL=http://127.0.0.1:4001 \
+REACT_APP_BACKEND_REALTIME_URL=ws://127.0.0.1:4001/ws \
+npm start
+```
+
+See `docs/DEVELOPMENT.md` for the full architecture (generic KV doc store, storage adapter interface, test layers) and `docs/REWORK_PLAN.md` for the design rationale.
 
 ## Project Structure
 
-`ttrpg-initiative-tracker/`
-- ` .dockerignore`        # Specifies intentionally untracked files that Docker should ignore
-- ` .env.example`         # Example environment variables
-- ` .env.local`           # Local environment variables (ignored by Git)
-- ` .gitignore`           # Specifies intentionally untracked files that Git should ignore
-- ` Dockerfile`           # Instructions to build the Docker image
-- ` package-lock.json`    # Records exact versions of dependencies
-- ` package.json`         # Project metadata and dependencies
-- ` postcss.config.js`    # PostCSS configuration (for Tailwind CSS)
-- ` tailwind.config.js`   # Tailwind CSS configuration
-- ` public/`              # Static assets
-  - ` favicon.ico`
-  - ` index.html`       # Main HTML template
-  - ` manifest.json`
-- ` src/`                 # React application source code
-  - ` App.js`           # Main application component
-  - ` index.css`        # Global styles (including Tailwind directives)
-  - ` index.js`         # React entry point
+<pre>
+ttrpg-initiative-tracker/
+├── .dockerignore        # Specifies intentionally untracked files that Docker should ignore
+├── .env.example         # Example environment variables
+├── .env.local           # Local environment variables (ignored by Git)
+├── .gitignore           # Specifies intentionally untracked files that Git should ignore
+├── Dockerfile           # Firebase-mode image (frontend-only, served by nginx)
+├── package.json         # Workspaces root: frontend + server + shared
+├── package-lock.json    # Records exact versions of dependencies
+├── postcss.config.js    # PostCSS configuration (for Tailwind CSS)
+├── tailwind.config.js   # Tailwind CSS configuration
+├── docker/              # Self-hosted deployment: Dockerfile, docker-compose.yml, Caddyfile
+├── docs/                # Rework plan, dev setup, testing, encounter-builder guide, glossary
+├── scripts/             # Manual demo/ops tooling (e.g. replay-combat.js)
+├── tests/               # Exploratory audit tooling (not part of the automated suite)
+├── public/              # Static assets
+│   ├── favicon.ico
+│   ├── index.html       # Main HTML template
+│   └── manifest.json
+├── src/                 # React frontend (Create React App)
+│   ├── App.js           # Main application component
+│   ├── storage/         # Storage adapter layer: firebase / ws / memory
+│   ├── index.css        # Global styles (including Tailwind directives)
+│   └── index.js         # React entry point
+├── server/              # Self-hosted backend: Express + ws + SQLite (better-sqlite3)
+└── shared/              # Framework-agnostic turn-order logic, used by frontend + server
+</pre>
+
+## Further Reading
+
+* `docs/DEVELOPMENT.md` — setup, running the backend, test suites
+* `docs/REWORK_PLAN.md` — why/how the self-hosted backend was added
+* `docs/TESTING.md` — test layers and how to run them
+* `docs/ENCOUNTER_BUILDER.md` — entity model and storage paths behind the DM interface
+* `docs/GLOSSARY.md` — domain terms (turn vs. round, etc.)
+* `TODO.md` — known bugs and backlog
 
 ## Contributing
 
-Feel free to fork the repository and submit pull requests. For major changes, please open an issue first to discuss what you would like to change.
+If you want to contribute, send me a message here: [https://discourse.draft13.com/c/ttrpg-initiative-tracker/16](https://discourse.draft13.com/c/ttrpg-initiative-tracker/16), and I can add to this Gitea instance and you can feel free to fork the repository and submit pull requests. For major changes, please pose a topic to the Discourse instance above linked above first to discuss what you would like to change.

TODO.md

@@ -0,0 +1,147 @@
+# TODO
+
+Backlog of bugs + long-term items. Milestones live in REWORK_PLAN.md.
+
+## Open
+
+### BUG: add participants duplication alert disappears fast
+- Duplicate-add throws alert but toast vanishes before user reads.
+- Fix: extend toast duration OR require manual dismiss.
+
+### FEAT: filter already-added from add-participant dropdown
+- Character list dropdown shows characters already in encounter.
+- Filter them out (or disable with strike-through).
+
+### FEAT-2: structured combat logs (parseable)
+- Goal: logs in storage carry enough state to run skip/rotation analysis
+  on ANY historic round — not just replay stdout.
+- Current: `{timestamp, message, encounterName, undo}`. Parser guesses
+  roster from message strings. Brittle.
+- Upgrade: structured fields at turn-state mutation log sites in App.js
+  (startEncounter, toggleActive, addParticipant, removeParticipant,
+  applyHpChange death/revive, togglePause, nextTurn):
+  ```
+  turnSnapshot: { round, currentTurnParticipantId, turnOrderIds, activeIds }
+  ```
+- Then `scripts/analyze-turns.js` ingests app logs directly. Works on real
+  game sessions, any round, deterministic.
+
+### FEAT-M6: transactional undo
+- Every mutating action writes event: `(type, payload, undo_payload, undone, ts)`.
+- Undo = apply `undo_payload` in same SQLite tx, flip `undone`. Transactional,
+  no stale clobber.
+- Replaces fragile `/logs` snapshot-write undo.
+- Migration: keep old undo for existing entries; new format for new.
+
+## Done (history)
+
+### Architecture: 1-list turn order model (slot, never sort)
+- Single source: turnOrderIds === participants.map(id). No re-sort after
+  startEncounter. nextTurn skips inactive (predicate), inactive stay in slot.
+- Drag (reorder) = same-init tie-break only. Cross-init blocked.
+- startEncounter sorts ALL participants by init once, then frozen.
+- addParticipant/updateParticipant slot by init (slotIndexForInit), preserve
+  drag order. Display renders participants[] directly (no sort).
+- Static guard test errs if `.sort(` reintroduced outside allowlist.
+- Design doc: docs/INITIATIVE_ORDERING.md.
+
+### Single source of truth: combat logic
+- All 15 App.js handlers delegate to @ttrpg/shared. ~498 lines inline dupes deleted.
+- shared/turn.js = only place turn logic lives.
+
+### Storage parity (firebase + server adapters)
+- Neutral queryConstraints ({__type:'orderBy'|'limit'}) honored by both adapters.
+- Shared contract test runs both identically. Memory adapter deleted; factory
+  throws on unknown mode.
+- ws storage mode renamed to server (env var + adapter name).
+
+### Logging contract
+- Every mutating op logs message + undo payload. No-op = null log.
+- Structural enforcement: per-op contract test (turn.logging.test.js) +
+  static source-scan guard (static.no-unlogged.test.js).
+
+### Custom conditions per campaign (DONE)
+- Freeform per-campaign conditions. Add applies to participant + persists to
+  campaign palette in one step. Badge render uses merged allConditions
+  (built-ins + custom). toggleCondition accepts any string. Dedup
+  case-insensitive. maxLength 40. Combat + replay tests prove arbitrary
+  string ids survive round-trip.
+
+### Death saves: D&D 5e model (DONE)
+- Separate success/fail tracking. deathSave(enc, id, type, n),
+  type='success'|'fail'. Fields: deathSaves, deathFails, isStable, isDying.
+  3 success=stable, 3 fail=dead. Returns {patch, log, status, isDying}.
+  Old single-counter broken (successes missing). Old data lost (feature
+  never worked in prod). UI: green ✓ + red ✕ rows, Stabilized/Dying badges.
+
+### FEAT-3: initiative first-class entry (DONE)
+- Initiative field at add-char, add-monster, edit participant.
+- Inline edit wired. Tie-break = drag order.
+
+### Test timeouts (DONE)
+- jest.setTimeout(10000) in setupTests.js (CRA blocks config-level timeout).
+
+### Warning = failure in tests (DONE)
+- console.error/warn throw in test env.
+
+### BUG-1: addParticipant + pause/resume corrupts rotation
+- RESOLVED as side effect of BUG-2 fix.
+
+### BUG-2: addParticipant allows duplicate id
+- FIXED (addParticipant throws on dup id).
+
+### BUG-4: hide-player-HP breaks display view
+- FIXED — mock honors setDoc{merge}, all 5 activeDisplay sites use merge.
+
+### BUG-5: mid-round addParticipant/revive corrupts rotation
+- FIXED — slot-array + DRY advance core nextActiveAfter.
+
+### BUG-6: reorderParticipants doesn't update turnOrderIds
+- FIXED structurally by 1-list model.
+
+### BUG-7: reorderParticipants not logged
+- FIXED — returns log:{message, undo}. Handler calls logAction. deathSave,
+  addParticipants, updateParticipant logging gaps also closed.
+
+### BUG-8: server adapter has no reconnect
+- FIXED — onclose reconnects + re-subscribes existing paths.
+
+### BUG-10: deact+reactivate same round double-acts participant
+- FIXED — 1-list model keeps slot position on toggle. Reactivate does not
+  grant second turn. Test: turn.bug10.test.js.
+
+### BUG-11: FE Combat.scenario test crashes
+- FIXED — moved to shared/turn.combat.test.js, pure functions, 100 rounds.
+
+### BUG-12: campaign selection follows activeDisplay
+- FIXED.
+
+### BUG-13: reorderParticipants crossing current pointer = ambiguous
+- FIXED — block cross-pointer reorder during active encounter (both dirs).
+  Full fix needs actedThisRound tracking. Pragmatic block prevents skip/double.
+  Pre-combat: free reorder. Test: turn.bug13.test.js.
+
+### BUG-14: addParticipant init-insertion breaks after drag-reorder
+- FIXED — slotIndexForInit scans current list (post-drag aware).
+
+### BUG-15: DisplayView re-sorts (drag order not preserved)
+- FIXED — display renders participants[] directly.
+
+### BUG-16: subscribeCollection hook drops queryConstraints
+- FIXED — neutral builders, both adapters honor orderBy/limit.
+
+### BUG-17: dead SDK imports in App.js
+- FIXED — trimmed (auth + getFirestore + getStorage remain).
+
+### BUG-18: stale comments reference deleted memory adapter
+- FIXED.
+
+### FEAT-1: Dead participants stay in turn order
+- DONE — applyHpChange no longer flips isActive on death. Dead stay in
+  rotation, nextTurn visits them, PCs get death-save turn.
+
+### combat.scenario 100 rounds not turns
+- DONE — loops by actual round-wrap count.
+
+### feat: add all characters to participants list
+- DONE — addParticipants bulk add wired.

docker/.dockerignore

@@ -4,28 +4,36 @@
 
 # Ignore Node.js modules (they will be installed in the Docker image)
 node_modules
+**/node_modules
 
 # Ignore build output (it will be generated in the Docker image)
 build
 dist
 
-# Ignore Docker files themselves
+# Ignore Docker files themselves (Caddyfile MUST stay in context for frontend build)
 Dockerfile
+Dockerfile.ws
 .dockerignore
+docker-compose.yml
 
 # Ignore any local environment files if you have them
 .env
-# .env.local
+.env.local
 .env.development.local
 .env.test.local
 .env.production.local
 
 # Ignore IDE and OS-specific files
 .vscode/
-.idea/
+.idea
 *.suo
 *.user
 *.userosscache
 *.sln.docstates
 Thumbs.db
 .DS_Store
+
+# Ignore local sqlite data + scratch diagnostics (never bake into image)
+data/
+scratch/
+tmp/

docker/Caddyfile

@@ -0,0 +1,18 @@
+# Caddyfile — single-container (caddy + node)
+# Caddy serves built frontend, proxies /api + /ws to node backend on :4001.
+# Node never exposed directly; only caddy on :80.
+
+:80 {
+	handle /api/* {
+		reverse_proxy 127.0.0.1:4001
+	}
+	handle /ws {
+		reverse_proxy 127.0.0.1:4001
+	}
+	# catch-all: static frontend (SPA fallback)
+	handle {
+		root * /srv
+		try_files {path} /index.html
+		file_server
+	}
+}

docker/Dockerfile

@@ -0,0 +1,54 @@
+# docker/Dockerfile — single container: caddy (front) + node (back).
+# Build context = repo root.
+# ---- build stage: frontend + install backend deps ----
+FROM node:18-alpine AS build
+WORKDIR /app
+
+COPY package*.json ./
+COPY shared/package.json ./shared/
+COPY server/package.json ./server/
+RUN npm install --include-workspace-root
+
+COPY shared/ ./shared/
+COPY server/ ./server/
+COPY src/ ./src/
+COPY public/ ./public/
+COPY tailwind.config.js postcss.config.js ./
+
+# better-sqlite3 native build (alpine musl)
+RUN cd server && npm rebuild better-sqlite3
+
+# build frontend (server storage, same-origin /api + /ws via caddy)
+ARG REACT_APP_TRACKER_APP_ID=ttrpg-initiative-tracker-default
+ENV REACT_APP_STORAGE=server
+ENV REACT_APP_TRACKER_APP_ID=$REACT_APP_TRACKER_APP_ID
+RUN NODE_OPTIONS=--openssl-legacy-provider npm run build
+
+# prune backend dev deps for runtime
+RUN npm prune --omit=dev
+
+# ---- runtime stage: caddy + node ----
+FROM node:18-alpine
+RUN apk add --no-cache caddy
+
+WORKDIR /app
+COPY --from=build /app/node_modules ./node_modules
+COPY --from=build /app/shared/node_modules ./shared/node_modules
+COPY --from=build /app/server/node_modules ./server/node_modules
+COPY --from=build /app/package*.json ./
+COPY --from=build /app/shared/package.json ./shared/
+COPY --from=build /app/server/package.json ./server/
+COPY shared/ ./shared/
+COPY server/ ./server/
+# built frontend served by caddy
+COPY --from=build /app/build /srv
+COPY docker/Caddyfile /etc/caddy/Caddyfile
+COPY docker/entrypoint.sh /entrypoint.sh
+
+ENV NODE_ENV=production
+ENV PORT=4001
+ENV DB_PATH=/data/tracker.sqlite
+
+EXPOSE 80
+WORKDIR /app
+CMD ["/entrypoint.sh"]

docker/docker-compose.yml

@@ -0,0 +1,23 @@
+# docker/docker-compose.yml — single container: caddy (front) + node (back).
+# Usage (from repo root):
+#   docker compose -f docker/docker-compose.yml up --build
+services:
+  app:
+    # no image: field => compose auto-names (docker-app), never pulls,
+    # always builds local. Service image private, never published.
+    build:
+      context: ..
+      dockerfile: docker/Dockerfile
+      args:
+        - REACT_APP_TRACKER_APP_ID=${TRACKER_APP_ID:-ttrpg-initiative-tracker-default}
+    ports:
+      - "${PORT:-8080}:80"
+    volumes:
+      - app-data:/data
+    environment:
+      - DB_PATH=/data/tracker.sqlite
+      - PORT=4001
+    restart: unless-stopped
+
+volumes:
+  app-data:

docker/entrypoint.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+# docker/entrypoint.sh — run node backend + caddy proxy in one container.
+# Caddy foreground (PID 1, handles signals). Node background.
+set -e
+
+# node backend (internal :4001)
+cd /app/server
+node index.js &
+NODE_PID=$!
+
+# caddy proxy (foreground, :80)
+exec caddy run --config /etc/caddy/Caddyfile --adapter caddyfile

docs/DEVELOPMENT.md

@@ -0,0 +1,287 @@
+# Development
+
+TTRPG Initiative Tracker — fork with self-hosted backend. Monorepo via npm workspaces.
+
+## Prerequisites
+
+- Node.js 22+
+- npm 10+
+
+## Layout
+
+```
+/
+  package.json              # workspaces root
+  src/                      # React frontend (CRA)
+    App.js                  # main app (~2900 lines)
+    storage/                # adapter layer (firebase/ws/memory + contract)
+    __mocks__/firebase/     # firebase SDK mock (Layer 1 tests)
+    tests/                  # frontend tests
+  server/                   # Backend: generic KV doc store (firebase mirror)
+    index.js                # REST (doc/coll/batch) + WS bootstrap
+    db.js                   # SQLite docs table, KV ops, broadcast
+    tests/                  # backend + adapter-vs-live tests
+  shared/                   # Pure logic, no I/O (client + server + tests import)
+    turn.js                 # turn-order state machine
+    tests/                  # turn logic tests
+  scripts/                  # manual demo tool (NOT test)
+    replay-combat.js        # live backend demo
+  tests/
+    audit/                  # exploratory bug-finders (manual, Math.random)
+      audit-rotation.js     # rotation invariant
+      audit-state.js        # 9 invariant classes
+  scratch/                  # gitignored: throwaway repro/exploration
+  docs/
+    REWORK_PLAN.md
+    DEVELOPMENT.md          # this file
+    GLOSSARY.md             # domain terms (turn vs round, etc)
+    ENCOUNTER_BUILDER.md    # DM interface guide
+    TESTING.md              # test + automation ops
+```
+
+## Setup
+
+```bash
+git clone git@github.com:keen99/ttrpg-initiative-tracker.git
+cd ttrpg-initiative-tracker
+npm install
+git config core.hooksPath .githooks   # enable pre-push test gate
+```
+
+## Run
+
+### Local dev stack (one command)
+
+```bash
+./scripts/dev-start.sh   # backend :4001 + frontend :3999, server mode
+./scripts/dev-stop.sh    # stop both
+```
+
+- backend: `npm run server:dev` (:4001, sqlite `data/tracker.sqlite`)
+- frontend: `npm start` (:3999, `REACT_APP_STORAGE=server`)
+- logs: `tmp/server.log`, `tmp/fe.log`
+
+Idempotent: if port busy, leaves existing proc as-is.
+
+Smoke check:
+```bash
+curl http://127.0.0.1:4001/health   # -> {"ok":true}
+```
+
+Never put db in `/tmp` (wipe risk). Use `./data/` (gitignored) or docker volume.
+
+### Manual (fallback)
+
+Backend:
+```bash
+npm run server:dev        # :4001, db: server/data/tracker.sqlite
+# or direct:
+DB_PATH=./data/tracker.sqlite PORT=4001 node server/index.js
+```
+
+Frontend (server mode):
+```bash
+REACT_APP_STORAGE=server \
+REACT_APP_BACKEND_URL=http://127.0.0.1:4001 \
+REACT_APP_BACKEND_REALTIME_URL=ws://127.0.0.1:4001/ws \
+BROWSER=none PORT=3999 \
+npm start
+```
+
+Opens http://127.0.0.1:3999/. Admin view `/`, player view `/display`.
+
+Firebase mode (default, upstream): set `REACT_APP_FIREBASE_*` in `.env.local` (copy `env.example`). `STORAGE_MODE=firebase` falls through to real SDK.
+
+## Test
+
+### Commands
+
+```bash
+npm run test:all          # shared + server (fast, no frontend)
+npm run shared:test       # pure turn logic
+npm run server:test       # adapter vs live backend
+npm test                  # CRA frontend (src/tests/, slow with scenario)
+```
+
+### Suites
+
+| Suite | Location | What | Count |
+|---|---|---|---|
+| Unit (turn logic) | `shared/tests/` | pure nextTurn, rotation, pause-add | 50 (1 skip) |
+| Integration (adapter vs backend) | `server/tests/` | ws adapter through live REST/WS | 23 |
+| Characterization (UI) | `src/tests/` | locks current App.js behavior | 62 |
+| Scenario | `src/tests/Combat.scenario.test.js` | 100-round full combat (240s) | 289 phases |
+
+Total: 134 green + 1 validated RED (skipped).
+
+### Test types
+
+- **Unit** = pure logic, fast, no I/O. Locks behavior of single functions.
+- **Integration** = real backend per test, adapter translation verified.
+- **Characterization** = render App via mock, assert current (buggy or not) UI behavior. Not desired-state.
+- **Scenario** = end-to-end flow through rendered App, asserts full sequence completes.
+- **Contract** = same spec run against every storage impl (memory, ws, firebase). Catches adapter drift.
+
+### Running one file / pattern
+
+```bash
+npm test --workspace shared -- --testPathPattern=round-rotation
+CI=true npx react-scripts test --watchAll=false src/tests/App.characterization.test.js
+```
+
+### Scenario test is slow
+
+`Combat.scenario.test.js` runs 100 combat rounds through rendered App — 240s timeout by design. Skip when iterating:
+
+```bash
+CI=true npx react-scripts test --watchAll=false --testPathIgnorePatterns="Combat.scenario"
+```
+
+## Demo tool (NOT test)
+
+`scripts/replay-combat.js` = live backend demo. Watch UI react to state changes.
+
+```bash
+# start backend + frontend first
+node scripts/replay-combat.js [rounds] [delayMs]
+# defaults: 100 rounds, 200ms/step
+```
+
+Coverage per round: damage, heal, all 22 conditions, toggleActive,
+removeParticipant, addParticipant (reinforcements), updateParticipant,
+pause/resume, reorderParticipants, endEncounter. Revives dead each round
+to sustain full round count.
+
+## Audit tools (NOT unit tests)
+
+`tests/audit/` = exploratory, Math.random, non-deterministic. Manual run.
+Unit tests (`{shared,server,src}/tests/`) lock known bugs deterministically.
+
+### audit-rotation.js
+
+Pure turn.js simulation of replay op sequence. Detects rotation violations
+(skip/dupe per round). Found BUG-1 (addParticipant + pause corrupts rotation).
+
+```bash
+node tests/audit/audit-rotation.js
+```
+
+Bisect: comment/uncomment op blocks to isolate triggering combo.
+
+### audit-state.js
+
+Runs pure turn.js combat, audits 9 invariant classes per round:
+
+1. rotation integrity (skip/dupe)
+2. HP bounds (0 ≤ hp ≤ max, no NaN)
+3. isActive consistency (dead = inactive)
+4. turnOrder no dup ids
+5. turnOrder ids all active
+6. currentTurn valid + active
+7. deathSave range (0 ≤ saves ≤ 3, reset on revive)
+8. removeParticipant orphans
+9. undo support
+
+```bash
+node tests/audit/audit-state.js [rounds]   # default 100
+```
+
+Current state (post BUG-1/2 fix): 0 violations / 100 rounds.
+
+See `TODO.md` for known bugs.
+
+## Scratch
+
+`scratch/` = gitignored throwaway. Repro scripts, exploration, debug.
+Not committed. Use freely, delete anytime.
+
+## Build
+
+```bash
+npm run build             # CRA production build -> build/
+```
+
+Docker build (existing, frontend-only):
+```bash
+docker build -t ttrpg-initiative-tracker .
+docker run -p 8080:80 --rm ttrpg-initiative-tracker
+```
+
+Full-stack docker-compose arrives in M5.
+
+## Storage architecture
+
+### Generic KV doc store
+
+Backend = firebase mirror. Single `docs` table: `path` (PK), `parent`, `data` (JSON), `updated_at`. Opaque JSON at arbitrary path strings. No shape-specific endpoints. App logic stays client-side.
+
+```
+Client (browser)                  Server
+  |                                 |
+  |-- storage.setDoc(path,data) -->|  REST PUT /api/doc
+  |<---- 200 ----------------------|
+  |                                 |
+  |-- storage.subscribeDoc(path) -->|  WS subscribe
+  |<---- WS {initial} --------------|  immediate value
+  |       ...                       |
+  |<---- WS {change} --------------|  on any write to path
+  |                                 |
+  Display / tablet                 |
+  |<---- WS {change} --------------|  same push
+```
+
+### Path normalization
+
+App passes firebase-prefixed paths (`artifacts/{APP_ID}/public/data/campaigns/...`). Adapter `norm()` strips prefix → bare canonical (`campaigns/...`). All impls share identity (contract test).
+
+### STORAGE_MODE flow
+
+`getStorageMode()` reads `REACT_APP_STORAGE` env (default `firebase`).
+- `firebase` → real SDK init
+- `server` → stub auth + db sentinel, route via `storage.*` adapter
+
+## Test layers
+
+- **Layer 1**: App vs firebase mock. Proves adapter call shape. Never exercises server adapter.
+- **Layer 2**: server adapter vs live backend. Proves translation + path identity.
+
+Both required — Layer 1 alone misses adapter bugs (path mismatch, no-op players, ws.on EventEmitter vs browser handlers).
+
+## Local pipeline (pre-push hook)
+
+Private repo = no free GitHub Actions. Tests run locally via git hook.
+
+`.githooks/pre-push` runs `npm run test:all` (shared + server, fast). Frontend tests not gated (slow).
+
+Skip:
+```bash
+git push --no-verify
+```
+
+Already configured on this checkout after `git config core.hooksPath .githooks`.
+
+## Status
+
+| Milestone | State |
+|---|---|
+| 0 repo/branch | ✅ done |
+| 1 backend + tests | ✅ done |
+| 2 frontend WS adapter | ✅ done |
+| 3 characterization tests | ✅ done (134 green) |
+| 4 skip fix + manual override | ⬜ next |
+| 5 docker compose | ⬜ |
+| 6 undo rework | ⬜ |
+| 7 playwright e2e | ⬜ deferred |
+
+See `docs/REWORK_PLAN.md` for full plan, `TODO.md` for known bugs.
+
+## Git
+
+- `origin` = `github.com:keen99/ttrpg-initiative-tracker` (this fork)
+- `upstream` = `code.draft13.com/robert/ttrpg-initiative-tracker` (friend's Gitea, read-only)
+- work branch: `rework-backend` (off `main`)
+
+```bash
+git fetch upstream         # pull friend's changes
+git merge upstream/main    # rebase our branch onto his
+```

docs/ENCOUNTER_BUILDER.md

@@ -0,0 +1,208 @@
+# Encounter Builder — DM Interface Guide
+
+How a DM (or LLM automating the DM role) builds and runs encounters via the UI and storage layer. Covers entity model, build flow, combat controls, and the storage paths backing each action.
+
+## Entity model
+
+Three nested entities. All stored as opaque JSON docs in the KV store (generic doc store — see `docs/DEVELOPMENT.md`).
+
+```
+Campaign
+  └─ Encounter(s)
+       └─ Participant(s)
+```
+
+Plus two global docs:
+- `activeDisplay/status` — controls player view (which campaign+encounter, hide-HP flag)
+- `logs/{id}` — append-only action log entries
+
+### Campaign
+
+Path: `artifacts/{APP_ID}/public/data/campaigns/{campaignId}`
+
+| Field | Type | Notes |
+|---|---|---|
+| `name` | string | |
+| `playerDisplayBackgroundUrl` | string | optional, image URL for player display bg |
+| `ownerId` | string | user id |
+| `createdAt` | ISO string | |
+| `players` | array | campaign-level character roster (templates, NOT combatants) |
+
+Campaign characters = reusable templates. Default HP + init mod. Added to any encounter via ParticipantManager. Not combatants themselves.
+
+### Encounter
+
+Path: `artifacts/{APP_ID}/public/data/campaigns/{campaignId}/encounters/{encounterId}`
+
+| Field | Type | Notes |
+|---|---|---|
+| `name` | string | |
+| `createdAt` | ISO string | |
+| `participants` | array | the combatants (see below) |
+| `round` | int | 0 = not started |
+| `currentTurnParticipantId` | string\|null | who acts now |
+| `isStarted` | bool | combat active |
+| `isPaused` | bool | frozen turn order (add/remove/edit allowed) |
+| `turnOrderIds` | array | participant ids in turn order = participants[] order (1-list model) |
+
+### Participant
+
+Object in `encounter.participants[]`:
+
+| Field | Type | Notes |
+|---|---|---|
+| `id` | string | `generateId()` |
+| `name` | string | |
+| `type` | `'character'` \| `'monster'` | character = PC (death saves), monster = hostile/NPC |
+| `originalCharacterId` | string\|null | links back to campaign character if type=character |
+| `initiative` | int | rolled once at add (`rollD20() + mod`). Stored value, not re-derived. |
+| `maxHp` | int | |
+| `currentHp` | int | 0 = dead/dying |
+| `isNpc` | bool | monster flagged NPC (display color, no death saves) |
+| `conditions` | array | condition ids from `CONDITIONS` list |
+| `isActive` | bool | in turn rotation? false = skipped by nextTurn |
+| `deathSaves` | int | PC only, 0-3 fails |
+| `isDying` | bool | death animation flag (player display) |
+
+## Build flow (UI)
+
+Admin view at `/`. Steps:
+
+### 1. Create campaign
+- Click **Create Campaign** button
+- Enter name + optional background URL
+- Submits → `setDoc(campaigns/{id}, { name, playerDisplayBackgroundUrl, ownerId, createdAt, players:[] })`
+
+### 2. Select campaign
+- Click campaign card → `setSelectedCampaignId(campaign.id)`
+- Now managing: CharacterManager + EncounterManager visible
+
+### 3. Add campaign characters (optional templates)
+CharacterManager section. Per character:
+- **Name**
+- **Default HP** (`DEFAULT_MAX_HP` = 10)
+- **Init Mod** (`DEFAULT_INIT_MOD` = 0)
+
+→ `updateDoc(campaign, { players:[...existing, newChar] })`
+
+These are reusable across encounters. Add to encounter later (auto-rolls initiative).
+
+### 4. Create encounter
+- Click **Create Encounter**
+- Enter name
+→ `setDoc(campaigns/{cid}/encounters/{eid}, { name, createdAt, participants:[], round:0, currentTurnParticipantId:null, isStarted:false, isPaused:false })`
+
+### 5. Add participants
+ParticipantManager section. Two paths:
+
+**Monster/NPC:**
+- **Monster Name** (`placeholder: "e.g., Dire Wolf"`)
+- **Init Mod** (`MONSTER_DEFAULT_INIT_MOD` = 2)
+- **Max HP** (`DEFAULT_MAX_HP` = 10)
+- **Is NPC?** checkbox (flag, changes display color)
+- Click **Add to Encounter**
+- Initiative auto-rolled: `rollD20() + mod`
+
+**Character (from campaign roster):**
+- Select character from dropdown
+- Click **Add to Encounter**
+- OR **Add All (Roll Init)** — bulk-adds all campaign chars, each rolls own initiative
+
+**Duplicate guard:** same `originalCharacterId` blocked (alerts "already in this encounter"). Monsters no dedup.
+
+Participant object added:
+```js
+{ id, name, type, originalCharacterId, initiative, maxHp, currentHp:maxHp,
+  isNpc, conditions:[], isActive:true, deathSaves:0, isDying:false }
+```
+
+### 6. Reorder before start (tie-break)
+Pre-combat only (`!isStarted || isPaused`). Drag handles shown for **tied initiative** values only. Drop reorders `participants[]` + `turnOrderIds`.
+
+Post-start drag: see BUG-13/14 in `TODO.md` (cross-init + pointer semantics untested).
+
+## Combat flow (UI)
+
+InitiativeControls panel (sticky, right side).
+
+### Start
+- **Start Combat** button (disabled if no active participants)
+- Sorts ALL participants by initiative (1-list: `participants[]` = display + turn order)
+- `round=1`, `currentTurnParticipantId` = first active, `isStarted=true`, `isPaused=false`
+- Sets `activeDisplay` → this campaign+encounter (player display syncs)
+- Initiative fixed at start. NOT re-derived from mod after.
+
+### Next Turn
+- **Next Turn** button (disabled if paused)
+- Advances to next active participant in `turnOrderIds`
+- Wraps at end → `round += 1`, re-sorts active by initiative at round start
+- Dead (`isActive:false`) skipped, stay in rotation
+
+### Pause / Resume
+- **Pause Combat** → `isPaused=true`, Next Turn disabled
+- While paused: add/remove participants, adjust HP, edit initiative, reorder ties
+- **Resume Combat** → `isPaused=false`, no re-sort (1-list: turnOrderIds already current)
+
+### HP adjustments (combat only)
+Per-participant input + buttons:
+- Number input
+- **Damage** (HeartCrack icon) — `currentHp = max(0, hp - amt)`
+- **Heal** (Heart icon) — `currentHp = min(maxHp, hp + amt)`
+- Death: hp→0 sets `isActive:false`, PC gets `deathSaves` tracking
+
+### Death saves (PC only, at 0 HP)
+3 buttons. Click marks fail. 3 fails = dead. Reset on revive/heal.
+
+### Conditions
+- Click participant → expand conditions picker (all 22 from `CONDITIONS`)
+- Active conditions show as badges, click to remove
+
+### End combat
+- **End Combat** button → resets `isStarted:false`, `round:0`, `currentTurn:null`, `turnOrderIds:[]`
+- Clears `activeDisplay` (player view goes blank)
+
+## Player display
+
+Separate view at `/display` or `?playerView=true`. Read-only second screen.
+
+What it shows:
+- Current encounter name
+- Round + current turn participant
+- All participants in `participants[]` order (drag order, NOT init-sorted — BUG-15 fix)
+- HP bars, conditions, death saves
+- Inactive monsters hidden (pre-staged reserves)
+
+Driven by `activeDisplay/status` doc. Controlled by **Open Player Window** button (sets active campaign+encounter) or Start Combat (auto-sets).
+
+## 1-list turn order model
+
+Key architecture. `turnOrderIds === participants.map(p => p.id)` always. Single source of truth.
+
+- **Display** = `participants[]` order (AdminView + DisplayView, no re-sort)
+- **Turn rotation** = `turnOrderIds` (mirrors participants[])
+- **Drag** = source of truth, overrides initiative
+- **Add mid-combat** = append to participants[] + sync (BUG-14: init-insert broken post-drag)
+- **Toggle active** = flip `isActive` only, stay in slot
+- **Remove** = drop from participants[] + sync, advance current if needed
+
+No re-sort after `startEncounter` except round-wrap (re-sorts active by init at top of round).
+
+## Storage paths quick reference
+
+```
+campaigns/{cid}                              campaign doc
+campaigns/{cid}/encounters/{eid}             encounter doc (participants[])
+campaigns/{cid}/encounters/{eid}/participants  ❌ NOT a path — participants inline
+activeDisplay/status                         player display control
+logs/{logId}                                 action log entry
+```
+
+## DM tips
+
+- Initiative rolled ONCE at add time. Stored. Edit via EditParticipantModal to override.
+- Pause before big roster changes (adds/removes). Resume re-syncs cleanly.
+- Campaign chars = templates. Edit campaign char doesn't touch encounter participants (already added).
+- Dead monsters stay in rotation, skipped. Remove via trash icon to clean list.
+- Player display auto-follows Start Combat. Manual control via Open Player Window.
+
+See `docs/GLOSSARY.md` for domain terms, `TODO.md` for known bugs.

docs/GLOSSARY.md

@@ -0,0 +1,59 @@
+# Glossary — TTRPG Initiative Tracker
+
+Domain terms used throughout the app, shared turn logic, tests, and docs. Keep
+these definitions stable so logs, UI labels, and code agree.
+
+## Combat structure
+
+| Term | Meaning |
+|------|---------|
+| **Initiative** | The ordered sequence determining who acts next. Rolled once at the start of an encounter; re-rolled only on a new encounter or explicit DM re-roll. |
+| **Round** | One full pass through initiative — every active participant gets exactly one turn. N participants (PCs + NPCs + monsters + features) = N turns per round. Round counter increments when initiative wraps back to the first participant. |
+| **Turn** | A single participant's initiative slot within a round. One participant acts. As many turns per round as there are participants. |
+| **Initiative slot** | Synonym for turn's position in the ordered list. |
+| **Top of round** | The first turn of a round (round counter increments here). |
+
+Example: encounter with 8 participants (3 PCs + 4 monsters + 1 NPC).
+
+```
+Round 1: turn 1 (Fighter) → turn 2 (Goblin1) → ... → turn 8 (Merchant)
+Round 2: turn 1 (Fighter) → ... → turn 8 (Merchant)   [round counter +=1 at top]
+```
+
+## Participants
+
+| Term | Meaning |
+|------|---------|
+| **Participant** | Any combatant tracked in initiative. Has HP, initiative roll, conditions, and an `isActive` flag. |
+| **PC** (Player Character) | Controlled by a player. On death → death saves (not removed from initiative). |
+| **NPC** (Non-Player Character) | DM-controlled ally/neutral (e.g. merchant, quest-giver). May or may not roll initiative. |
+| **Monster** | Hostile DM-controlled combatant. On death → typically removed from active initiative or marked dead. |
+| **Feature / Lair** | Environmental or legendary effect that occupies an initiative slot (e.g. lair action at initiative 20). |
+
+## Participant state
+
+| Term | Meaning |
+|------|---------|
+| **HP** (Hit Points) | Current health. `currentHp` / `maxHp`. At 0 → dying or dead (rules differ by type). |
+| **Initiative mod** | Bonus added to d20 initiative roll. `defaultInitMod`. |
+| **Conditions** | Temporary status effects (stunned, prone, poisoned, etc.) applied/toggled during play. Array on participant. |
+| **isActive** | Whether the participant is in the active initiative rotation. Set false on death (CURRENT behavior — see M4 skip-bug fix). |
+| **Death save** | PC-only mechanic. Successes/failures tracked at 0 HP. 3 fails → dead; 3 successes → stable. |
+
+## Views
+
+| Term | Meaning |
+|------|---------|
+| **Admin view** (`/`) | DM interface. Full create/edit/combat control. |
+| **Player view** (`/display` or `?playerView=true`) | Read-only second-screen display for players. Shows current turn, HP bars, conditions, round. No DM controls. |
+| **Active display** | The single `activeDisplay/status` doc controlling what the player view shows (which campaign/encounter, hide-player-HP flag). |
+
+## Backend / storage
+
+| Term | Meaning |
+|------|---------|
+| **Adapter** | `src/storage/{firebase,server}.js`. Contract boundary between App and backend. App only calls `storage.*`, never raw SDK/fetch. |
+| **Path normalization** (`norm()`) | Strip firebase prefix (`artifacts/{APP_ID}/public/data/`) → bare canonical path (`campaigns/X`). Runs inside every adapter method. |
+| **Generic KV doc store** | Backend stores opaque JSON at arbitrary path strings. No shape-specific endpoints. Backend = firebase mirror, not REST API for app entities. |
+| **Layer 1 test** | App vs firebase mock. Proves adapter call shape. |
+| **Layer 2 test** | server adapter vs live backend. Proves translation + path identity. |

docs/INITIATIVE_ORDERING.md

@@ -0,0 +1,59 @@
+# Initiative Ordering — Design
+
+## Core Principle
+
+**Slot, never sort.**
+
+Initiative order = a single list. Participants occupy slots determined by
+initiative value. The list is mutated by insert/move operations — never
+re-sorted wholesale.
+
+## Single Source of Truth
+
+One list: `participants[]`.
+
+- Display order = `participants[]` order (both Player view + DM view).
+- Turn order = `participants[]` order.
+- No derived/re-sorted copy. `turnOrderIds`, if present, is always an exact
+  mirror (`participants.map(p => p.id)`) — never an independent ordering.
+
+## When Ordering Changes
+
+| Action | Effect on order |
+|--------|-----------------|
+| **Add** (roll or manual) | Insert participant into slot by initiative |
+| **Edit initiative** | Move participant to new slot |
+| **Drag** | Reorder within a tie (same initiative) only |
+| **Remove** | Splice out; others keep position |
+| **Start encounter** | Freeze current list. No re-sort. |
+| **Round wrap** | No rebuild. Continue rotation through existing list. |
+| **Damage/heal/death/save** | No order change. |
+| **Toggle active** | No position change. Skip in rotation only. |
+
+## Slotting Rules
+
+- Insert/move positions participants so the list stays initiative-descending.
+- **Tie-break = original add order.** Later additions slot *after* existing
+  same-init participants. Stable insertion.
+- Tie order is only changed by explicit DM drag. Never auto-changed.
+
+## Drag (DM Tie-Break Override)
+
+- Only participants with the **same initiative** are draggable onto each other.
+- Cross-initiative drag is **not allowed**. (Use edit-initiative field instead.)
+- Drag persists in `participants[]`. Survives all subsequent operations.
+- **Re-slotting on add/edit must preserve drag-established tie order.**
+
+## Explicitly Forbidden
+
+- `sort()` on every mutation. Overwrites drag order. Root cause of past drift.
+- Separate display order vs turn order. Causes player/DM divergence.
+- Re-sort on round wrap. Replays rounds, introduces skips.
+- Cross-initiative drag. Contradicts initiative as the primary key.
+- Auto-changing tie order on add/edit. Silently loses DM intent.
+
+## Why
+
+Sorting is destructive to manual ordering. A stable slot list with drag for
+ties gives deterministic, DM-controllable order that never drifts between
+display surfaces or combat rounds.

docs/REWORK_PLAN.md

@@ -0,0 +1,266 @@
+# Initiative Tracker — Rework Plan
+
+Status: **APPROVED — executing**
+Owner: draistrick (fork → `keen99/ttrpg-initiative-tracker`, private)
+Upstream: `code.draft13.com/robert/ttrpg-initiative-tracker` (friend's Gitea)
+
+---
+
+## Goals
+
+1. **Replace Firebase with self-hosted backend.** Browser cannot own a DB file (sandbox). Cross-device (DM + tablet + player view) requires a real backend. Backend is the foundation, built first.
+2. **Automated test ecosystem as the baseline.** Lock current behavior before changing it.
+3. **Remain mergeable upstream.** Default behavior (Firebase) preserved behind flag. Upstream `main` stays clean. Friend keeps Firebase path.
+4. **Self-hostable in local Docker** (in-house network). Public exposure = future, only after auth + multiuser safety.
+
+## Non-Goals (this plan)
+
+- Ripping Firebase. Kept as default adapter upstream.
+- Public/multiuser deployment. Deferred.
+- Rewriting the entire 2935-line `App.js`. Only extract what testability demands.
+- Feature/bug work. That lives in `TODO.md`. This plan = infra + backend + test harness only.
+
+---
+
+## Problem Statement
+
+### Why Firebase is wrong here (for this fork)
+- Requires Google account + network for a single-user tabletop tool.
+- Realtime value (DM view ↔ player display) is real but solvable locally.
+- API key baked into client bundle (CRA `REACT_APP_*` at build); security depends entirely on console rules not in repo.
+- Vendor lock + quota; `onSnapshot` on collections burns reads.
+- Friend keeps it; we fork off it.
+
+### Why a backend is mandatory
+Browser sandbox cannot write the filesystem. No sqlite file, no `/data/db.sqlite`, nothing. Browser JS is blocked from disk by design. Therefore cross-device storage (DM ↔ tablet ↔ player view) requires a separate Node process owning the DB file and serving the browser over HTTP/WebSocket. There is no browser-only path. **The backend is step one, not deferred.**
+
+---
+
+## Architecture
+
+### Stack (locked)
+- **Node.js** runtime
+- **Express** web framework
+- **ws** WebSocket lib (realtime push, replaces `onSnapshot`)
+- **better-sqlite3** SQLite driver (synchronous, simple, fast)
+- **SQLite** DB (single file, docker volume, trivial backup)
+- **Jest** test runner (already in CRA deps)
+
+Postgres deferred until public multiuser exposure is real. SQLite schema ports easily if that day comes.
+
+### Backend design
+- Owns SQLite file. Only writer.
+- Holds authoritative state.
+- Generic KV doc store (firebase mirror): single `docs` table (path PK, parent, data JSON, updated_at). Opaque JSON at arbitrary path strings. No shape-specific endpoints. App logic stays client-side.
+- WS broadcast on every state change → all connected clients (DM view, player display, tablet) update instantly.
+
+### Three storage impls, one interface (frontend)
+
+The storage interface is the test seam and the upstream-compat layer.
+
+| Impl | When used | Automated-tested? |
+|---|---|---|
+| `firebase.js` | default (`STORAGE=firebase`) — upstream path | No — requires live Firebase project |
+| `server.js` | `STORAGE=server` — our fork, talks to backend | Yes — against running backend |
+| `memory.js` | test-only, in-process | Yes — fast, deterministic |
+
+**Frontend interface contract** (all three implement):
+- `getDoc(path)`, `setDoc(path, data, opts)`, `updateDoc(path, patch)`
+- `deleteDoc(path)`, `batch(ops)`
+- `subscribeDoc(path, cb)` / `subscribeCollection(path, cb)` → real-time push
+
+Firebase impl: existing `onSnapshot` + SDK calls, moved verbatim behind interface (M2).
+WS impl: thin adapter; generic KV ops, receives **state updates** via WS subscribe (M2).
+Memory impl: in-memory Map + EventEmitter, for tests (M3).
+
+### Repo layout (npm workspaces)
+
+```
+/
+  package.json              # workspaces root
+  src/                      # React frontend (existing, refactored behind storage interface)
+    storage/
+      index.js              # factory: pick impl from STORAGE env
+      firebase.js           # extracted from current App.js (verbatim)
+      server.js             # talks to backend (was ws.js)
+      memory.js             # NEW — test only
+      contract.js           # interface spec (runStorageContract)
+    tests/                  # frontend tests
+  server/                   # NEW
+    index.js                # Express + ws bootstrap, generic KV REST
+    db.js                   # better-sqlite3, docs table (KV), broadcast
+    handlers.js             # REST handlers
+    tests/                  # adapter vs live backend (Layer 2 test)
+  shared/                   # pure logic, no I/O, importable by client + server + tests
+    turn.js                 # turn logic (single source; tests import)
+    tests/                  # turn logic unit tests (characterization + desired)
+  data/                     # gitignored sqlite DB
+  docker-compose.yml        # NEW — M5
+  docs/
+    REWORK_PLAN.md          # this file
+    DEVELOPMENT.md
+    GLOSSARY.md
+  TODO.md                   # bugs + features (separate from this plan)
+```
+
+### Auth
+- **Now:** `AUTH_MODE=none`. App gated by nginx HTTP basic auth (reuse friend's existing pattern). In-house only. Risk acceptable: someone sees your initiative counter.
+- **Future:** `AUTH_MODE=token` — real login, real users. Only if/when publicly exposed. Not built this plan.
+
+---
+
+## Milestones
+
+Each milestone = independently mergeable PR upstream (unless marked ❌).
+
+| M | Does | Tests? |
+|---|---|---|
+| 0 | repo, branch, remotes | no |
+| 1 | build backend (Node+Express+WebSocket+better-sqlite3) | unit tests as built |
+| 2 | frontend WS adapter — app runs vs backend, cross-device works | yes |
+| 3 | characterization tests lock current behavior | yes |
+| 4 | resolve initiative rotation corruption (BUG-5) | yes |
+| 5 | docker single container (caddy+node) | smoke ✅ |
+| 6 | _moved to TODO backlog (feature work)_ | - |
+| 7 | playwright multi-window e2e (deferred) | e2e |
+| 8 | (future) public exposure | - |
+
+### Milestone 0 — Repo + branch setup ✅
+- Fresh branch off `main` (not `dsr-rework`). Name: `rework-backend`.
+- `upstream` remote = friend's Gitea (read-only fetch).
+- Push origin = `keen99/ttrpg-initiative-tracker` (private).
+- npm workspaces root config.
+- Commit this plan.
+- **Exit criteria:** clean branch, plan committed, remotes set. ✅ DONE.
+- **Upstream-PRable:** n/a (fork infra)
+
+### Milestone 1 — Build backend ✅
+- `server/`: Express + WebSocket + better-sqlite3.
+- Generic KV doc store (firebase mirror): `docs` table (path PK, parent, data JSON, updated_at). REST: GET/PUT/PATCH/DELETE `/api/doc?path=`, GET `/api/collection?path=`, POST `/api/collection`, POST `/api/batch`. WS: subscribe by path.
+- Server holds authoritative state. No turn logic server-side (logic stays client-side in `shared/turn.js`).
+- **Exit criteria:** backend boots, serves state over WS, persists to SQLite, unit tests green. ✅ DONE.
+- **Upstream-PRable:** ❌ divergence (friend stays Firebase).
+
+### Milestone 2 — Frontend WS adapter ✅
+- Define `storage/contract.js` interface spec.
+- Move all Firestore call sites from `App.js` into `storage/firebase.js` behind interface (verbatim).
+- Implement `storage/server.js` per interface, talking to backend. Generic KV ops, subscribes via WebSocket.
+- Implement `storage/memory.js` for frontend unit tests.
+- `storage/index.js` factory: `STORAGE` env → pick impl. Default `firebase` (upstream unchanged).
+- App runs against backend with `STORAGE=server`.
+- Cross-device verified manually: DM view + player display + tablet.
+- **Exit criteria:** app runs fully against local backend, no Firebase. Multi-device sync works. ✅ DONE.
+- **Upstream-PRable:** ⚠️ partial. Storage interface + firebase extract = ✅. WS impl = ❌.
+
+### Milestone 3 — Characterization tests lock current behavior ✅
+- Lock current behavior via tests.
+- Cover: START, NEXT_TURN, PAUSE, RESUME, ADD_PARTICIPANT, REMOVE_PARTICIPANT, TOGGLE_ACTIVE, REORDER, APPLY_DAMAGE/HEAL, DEATH_SAVE, END.
+- Two layers: Layer 1 (App + firebase mock, proves call shape), Layer 2 (server adapter vs live backend, proves translation).
+- Iterate until confident: baseline solid, regressions impossible to silently slip.
+- **Exit criteria:** characterization suite green. Baseline locked. ✅ DONE.
+- **Upstream-PRable:** ✅ if kept storage-agnostic (tests target turn logic shape).
+
+### Milestone 4 — Resolve initiative rotation corruption (BUG-5) ✅
+- **Fixed** (commit `494327f`).
+- Slot-array turn order model + DRY advance core (`nextActiveAfter`).
+  Both `nextTurn` + `computeTurnOrderAfterRemoval` delegate → one advance
+  path, no drift.
+- 500-round replay: 0 skips, 0 double-acts.
+- Tests: `turn.skip.test.js`, `turn.dry.test.js` (advance parity lock).
+- **Upstream-PRable:** ✅ bug fix.
+
+### Milestone 5 — Docker compose ✅
+- Single container: caddy (front, static + proxy) + node backend (internal :4001).
+- Files in `docker/` tree (kept separate from upstream root Dockerfile):
+  - `docker/Dockerfile` — build FE + BE, runtime caddy+node
+  - `docker/Caddyfile` — proxy /api + /ws (WebSocket path) to node, static SPA fallback
+  - `docker/entrypoint.sh` — node bg + caddy fg
+  - `docker/docker-compose.yml` — one `app` service, volume for sqlite
+- Run: `docker compose -f docker/docker-compose.yml up --build` (or `cd docker && docker compose up --build`). Port 8080.
+- No `image:` field => compose auto-names, never pulls service image (private).
+- **Exit criteria:** `docker compose up` runs full stack in-house. ✅ DONE.
+  - Verified: REST roundtrip, WS subscribe+push, replay 20 rounds CLEAN (0 skips/doubles/shifts), UI styled (Tailwind compiles).
+- **Upstream-PRable:** ✅ separate docker/ tree, root Dockerfile untouched, firebase default preserved.
+
+### Milestone 6 — Undo rework — _MOVED to TODO backlog_
+- Moved: feature work (transactional undo), not infra. Lives in `TODO.md` now.
+- Scope: events table `(type, payload, undo_payload, undone, ts)`; undo = apply undo_payload in tx.
+
+### Milestone 7 — Playwright E2E (deferred)
+- Multi-window E2E: DM view + display + player view in separate browser contexts against running backend.
+- Verify realtime sync end-to-end.
+- **Only build if sync regresses or we deviate significantly.** Turn-logic unit + backend integration tests cover most regression risk cheaper.
+- **Exit criteria:** e2e green for core combat flow across 3 windows.
+- **Upstream-PRable:** ✅ if test infra shared.
+
+### Milestone 8 — (Future) Public exposure
+- Real auth (`AUTH_MODE=token`).
+- Rate limiting, CSRF, hardening.
+- Postgres migration if load warrants.
+- Only if we decide to expose publicly + multiuser.
+
+---
+
+## Testing strategy
+
+### Layers
+1. **Turn logic unit tests** (Jest, pure functions, `shared/tests/`). Characterization + desired. Cheap, essential.
+2. **Backend integration tests** (Jest, `server/tests/`) — spin server on random port, assert WS pushes + SQLite persists + transactional correctness.
+3. **Frontend adapter contract tests** (Jest, `src/tests/`) — impl parity against interface (memory). Firebase mock harness for Layer 1 App tests.
+
+### Characterization → desired
+1. **Characterization** — capture current behavior exactly (bugs included). Locks extraction/port as provably identical. Lets later fix be provable.
+2. **Desired-behavior (red)** — write what *should* happen. Fail today. Fix → green. Bug stays dead. (Bug fixes live in TODO.md, tracked separately.)
+
+### Manual smoke via config flags
+- `STORAGE=firebase` → current behavior (friend's path, upstream default).
+- `STORAGE=server` → our path, local backend.
+- docker-compose profiles mirror the above.
+
+### Accepted test gap
+- Firebase adapter untested (requires live project). Accepted cost.
+- Mitigated by: interface contract; if firebase impl drifts, integration smoke only.
+
+---
+
+## Mergeability upstream
+
+| Milestone | Upstream-PRable? | Why |
+|---|---|---|
+| 0 repo setup | n/a | fork infra |
+| 1 backend | ❌ | divergence (friend stays Firebase) |
+| 2 WS adapter | ⚠️ partial | interface + firebase extract ✅, WS ❌ |
+| 3 characterization tests | ✅ | if storage-agnostic |
+| 4 BUG-5 rotation fix | ✅ | bug fix |
+| 5 docker | ✅ | separate docker/ tree, root Dockerfile untouched, firebase preserved |
+| 6 undo (moved to TODO) | - | - |
+| 7 playwright | ✅ | if test infra shared |
+
+Default `STORAGE=firebase` + `AUTH_MODE=none` (unset) = upstream sees literally zero change.
+
+---
+
+## Risks
+
+- **CRA + workspaces friction.** Create React App may resist monorepo layout. Mitigation: keep `src/` as CRA root, `server/` + `shared/` as separate workspaces imported via alias. Eject/craco only if forced.
+- **Firebase drift untested.** Mitigation: interface contract; friend's path his to maintain.
+- **Undo history migration.** Existing log entries use old snapshot format. Mitigation: keep old undo working until cleared, new format for new entries.
+- **WS reconnect/state-sync edge cases.** Transient drop mid-combat. Mitigation: client requests full state resync on (re)connect; server is source of truth.
+
+---
+
+## Decisions (locked)
+
+1. **Branch:** `rework-backend` off `main`.
+2. **npm workspaces** for `server/` + `shared/` alongside CRA `src/`. Fallback alias if CRA fights.
+3. **Backend = generic KV doc store** (firebase mirror), not shape-specific endpoints. Thin adapter passthrough. Opaque JSON at arbitrary path strings.
+
+---
+
+## Current status
+
+- M0 ✅, M1 ✅, M2 ✅, M3 ✅, M4 ✅, M5 ✅
+- Backend live: port 4001, db `./data/tracker.sqlite`
+- Frontend: port 3999 with `REACT_APP_STORAGE=server`
+- Test suite: ~160 tests (shared + server + FE). Bugs tracked in `TODO.md`.
+- Next milestones: M5 docker-compose. Undo moved to TODO backlog.

docs/TESTING.md

@@ -0,0 +1,233 @@
+# Testing & Automation — Operating Guide
+
+How to run tests, demos, audits, docker stack, and understand the test layers. For any LLM session picking up this repo.
+
+## Test commands
+
+```bash
+npm run test:all        # shared + server (fast, ~2s) — pre-push gate
+npm run shared:test     # pure turn logic (shared/turn.js)
+npm run server:test     # ws adapter vs live backend
+npm test                # CRA frontend (src/tests/, slow w/ scenario)
+```
+
+Pre-push hook (`.githooks/pre-push`) runs `npm run test:all`. Frontend not gated (slow). Skip: `git push --no-verify`.
+
+Setup hook once per clone:
+```bash
+git config core.hooksPath .githooks
+```
+
+## Test suites
+
+| Suite | Location | What | Count |
+|---|---|---|---|
+| Unit (turn logic) | `shared/tests/` | pure nextTurn, rotation, pause-add, dead-skip, reorder, round, invariant, dry | 90 |
+| Integration (adapter vs backend) | `server/tests/` | ws adapter through live REST/WS | 24 |
+| Characterization (UI) | `src/tests/` | locks current App.js behavior | 66 |
+| ESM guard | `src/tests/StorageEsm.test.js` | no CJS in adapters | 4 |
+
+Total: ~184. 1 known RED (BUG-4 HideHpToggle, backlog).
+
+### Run one file / pattern
+
+```bash
+npm test --workspace shared -- --testPathPattern=round-rotation
+npm run server:test -- tests/ws-reconnect
+CI=true npx react-scripts test --watchAll=false --testPathPattern="DisplayView.drag-order"
+```
+
+Frontend uses `react-scripts test` (CRA). Always set `CI=true` + `--watchAll=false` for single runs.
+
+## Test layers (important)
+
+Two layers, both required:
+
+- **Layer 1**: App vs firebase mock (`src/__mocks__/firebase/`). Proves adapter call shape. Never exercises ws adapter.
+- **Layer 2**: ws adapter vs live backend (`server/tests/`). Proves translation + path identity.
+
+Layer 1 alone misses adapter bugs (path mismatch, no-op players, ws event handler bugs). Layer 2 catches those.
+
+## Test types
+
+| Type | Purpose |
+|---|---|
+| **Unit** | pure logic, fast, no I/O. Locks single function behavior. |
+| **Integration** | real backend per test (port 0 = OS picks free). Adapter translation verified. |
+| **Characterization** | render App via mock, assert current UI behavior (buggy or not). NOT desired-state. |
+| **Contract** | same spec run against every storage impl (memory, ws, firebase). Catches adapter drift. |
+| **Scenario** | end-to-end flow through rendered App. `Combat.scenario.test.js` = 100 rounds, ~240s. Pre-existing crash (BUG-11). |
+
+## TDD discipline
+
+RED first → fix → GREEN. Never change functional code to pass tests for existing state without test driving it.
+
+- Find bug → write failing test (RED)
+- Fix code → test passes (GREEN)
+- Log confirmed bug in `TODO.md`
+- One bug at a time, commit with evidence
+
+## Replay tool (demo, NOT unit test)
+
+`scripts/replay-combat.js` — drives full combat via ws adapter (same contract as App) against live backend. UI updates in real-time if frontend running.
+
+```bash
+# start backend + frontend first
+node scripts/replay-combat.js [rounds] [delayMs]
+# defaults: 100 rounds, 200ms/step
+# faster: 20 400 = 20 rounds, 400ms each
+
+# against docker stack:
+BACKEND_URL=http://127.0.0.1:8080 node scripts/replay-combat.js 20 400
+```
+
+Coverage per round: damage, heal, all 22 conditions, toggleActive, removeParticipant, addParticipant (reinforcements), updateParticipant, pause/resume, reorderParticipants, endEncounter. Revives dead each round to sustain count.
+
+Output → log file, then analyze:
+
+```bash
+node scripts/replay-combat.js 20 400 > tmp/run.log 2>&1
+node scripts/analyze-turns.js tmp/run.log
+```
+
+Exit 0 = clean. Reports skips, double-acts, order shifts.
+
+### analyze-turns.js
+
+Parses replay log. Detects:
+- **real skips**: active participant not acted in a round
+- **double-acts**: same participant twice in a round
+- **order shifts**: turnOrderIds changed unexpectedly
+
+Handles `[pointer X→Y wrap]` events (mutation-driven advance) and `[reorder A→before B]`. Logs `order=[Name:init,...]` + `parts=[Name:init,...]` per turn. Parser blind to DisplayView render (separate concern — FE test covers that).
+
+Round marker: `--- round N starting ---` (top of loop, post-fix).
+
+## Audit tools (NOT unit tests)
+
+`tests/audit/` — exploratory, `Math.random`, non-deterministic. Manual run. NOT jest.
+
+### audit-rotation.js
+Pure turn.js simulation of replay op sequence. Detects rotation violations. Found BUG-1.
+
+```bash
+node tests/audit/audit-rotation.js
+```
+
+### audit-state.js
+Runs pure turn.js combat. Audits 9 invariant classes per round:
+1. rotation integrity (skip/dupe)
+2. HP bounds (0 ≤ hp ≤ max, no NaN)
+3. isActive consistency (dead = inactive)
+4. turnOrder no dup ids
+5. turnOrder ids all active
+6. currentTurn valid + active
+7. deathSave range (0-3, reset on revive)
+8. removeParticipant orphans
+9. undo support
+
+```bash
+node tests/audit/audit-state.js [rounds]   # default 100
+```
+
+Current state: 0 violations / 100 rounds (post BUG-1/2 fix).
+
+## Docker stack
+
+Single container: caddy (front, static + proxy) + node backend (internal :4001).
+
+```bash
+# build + run (from repo root)
+docker compose -f docker/docker-compose.yml up --build -d
+# → http://127.0.0.1:8080
+
+# logs
+docker compose -f docker/docker-compose.yml logs app --tail 20
+
+# stop
+docker compose -f docker/docker-compose.yml down
+
+# rebuild after code change
+docker compose -f docker/docker-compose.yml up -d --build
+```
+
+Files:
+- `docker/Dockerfile` — build FE + BE, runtime caddy+node
+- `docker/Caddyfile` — proxy /api + /ws to node, static SPA fallback
+- `docker/entrypoint.sh` — runs node bg + caddy fg
+- `docker/docker-compose.yml` — one `app` service, volume for sqlite
+
+### Verify docker stack
+
+```bash
+# REST roundtrip
+curl -s -X PUT http://127.0.0.1:8080/api/doc -H 'Content-Type: application/json' \
+  -d '{"path":"campaigns/test","data":{"name":"X"}}' >/dev/null
+curl -s "http://127.0.0.1:8080/api/doc?path=campaigns/test"
+
+# WS subscribe + push (node one-liner, see scripts)
+# Full combat: replay against docker
+BACKEND_URL=http://127.0.0.1:8080 node scripts/replay-combat.js 20 400 > tmp/docker.log 2>&1
+node scripts/analyze-turns.js tmp/docker.log
+```
+
+### Inspect docker sqlite
+
+```bash
+docker exec docker-app-1 sh -c 'node -e "
+const db=require(\"better-sqlite3\")(\"/data/tracker.sqlite\");
+const rows=db.prepare(\"SELECT path, substr(data,1,50) as d FROM docs\").all();
+console.log(\"count=\"+rows.length);
+rows.forEach(r=>console.log(r.path+\" => \"+r.d));
+"'
+```
+
+## Dev servers (non-docker)
+
+### Backend
+```bash
+npm run server:dev        # :4001, db: ./data/tracker.sqlite
+# or:
+DB_PATH=./data/tracker.sqlite PORT=4001 node server/index.js
+curl http://127.0.0.1:4001/health   # → {"ok":true}
+```
+
+Never db in `/tmp` (wipe risk). Use `./data/` (gitignored) or docker volume.
+
+### Frontend (server mode)
+```bash
+REACT_APP_STORAGE=server \
+REACT_APP_BACKEND_URL=http://127.0.0.1:4001 \
+REACT_APP_BACKEND_REALTIME_URL=ws://127.0.0.1:4001/ws \
+BROWSER=none PORT=3999 \
+npm start
+```
+→ http://127.0.0.1:3999/. Admin `/`, player `/display`.
+
+Firebase mode (default): set `REACT_APP_FIREBASE_*` in `.env.local` (copy `env.example`).
+
+## Storage modes
+
+`STORAGE_MODE = getStorageMode()` reads `REACT_APP_STORAGE`:
+- `firebase` (default) → real SDK
+- `server` → backend (docker/prod)
+
+All adapters ESM. Adapter contract: `src/storage/contract.js` — same spec vs server/firebase.
+
+## Known RED / backlog
+
+- BUG-4: HideHpToggle RED (setDoc→updateDoc, clobbers activeDisplay)
+- BUG-10: deact+reactivate double-act
+- BUG-11: Combat.scenario test crash
+- BUG-13: reorder cross-pointer semantics
+- BUG-14: addParticipant init-insert post-drag
+
+See `TODO.md` for full list + status.
+
+## Scratch
+
+`scratch/` — gitignored throwaway. Repro scripts, exploration, debug. Not committed. Use freely, delete anytime.
+
+## Status
+
+See `docs/REWORK_PLAN.md` for milestones, `TODO.md` for bugs, `docs/DEVELOPMENT.md` for setup, `docs/GLOSSARY.md` for terms, `docs/ENCOUNTER_BUILDER.md` for DM interface.

env.example

@@ -6,4 +6,11 @@ REACT_APP_FIREBASE_STORAGE_BUCKET="YOUR_FIREBASE_STORAGE_BUCKET_HERE"
 REACT_APP_FIREBASE_MESSAGING_SENDER_ID="YOUR_FIREBASE_MESSAGING_SENDER_ID_HERE"
 REACT_APP_FIREBASE_APP_ID="YOUR_FIREBASE_APP_ID_HERE"
 
-REACT_APP_TRACKER_APP_ID="ttrpg-initiative-tracker-default"
+REACT_APP_TRACKER_APP_ID="ttrpg-initiative-tracker-default"
+
+# --- Self-hosted backend mode (optional) ---
+# Default storage = firebase (SDK). Set REACT_APP_STORAGE=server to use the
+# bundled Express + WebSocket backend (server/) instead.
+# REACT_APP_STORAGE="server"
+# REACT_APP_BACKEND_URL="http://127.0.0.1:4001"
+# REACT_APP_BACKEND_REALTIME_URL="ws://127.0.0.1:4001/ws"

nginx-docker.conf

@@ -0,0 +1,9 @@
+server {
+    listen 80;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+}

package.json

@@ -2,25 +2,32 @@
   "name": "ttrpg-initiative-tracker",
   "version": "0.1.0",
   "private": true,
+  "workspaces": [
+    "server",
+    "shared"
+  ],
   "dependencies": {
     "@testing-library/jest-dom": "^5.17.0",
-    "@testing-library/react": "^13.4.0",
     "@testing-library/user-event": "^13.5.0",
+    "autoprefixer": "^10.4.19",
     "firebase": "^10.12.2",
     "lucide-react": "^0.395.0",
+    "postcss": "^8.4.38",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
     "react-scripts": "5.0.1",
-    "web-vitals": "^2.1.4",
-    "autoprefixer": "^10.4.19",
-    "postcss": "^8.4.38",
-    "tailwindcss": "^3.4.3"
+    "tailwindcss": "^3.4.3",
+    "web-vitals": "^2.1.4"
   },
   "scripts": {
     "start": "react-scripts start",
     "build": "react-scripts build",
     "test": "react-scripts test",
-    "eject": "react-scripts eject"
+    "eject": "react-scripts eject",
+    "server:dev": "npm run dev --workspace server",
+    "server:test": "npm test --workspace server",
+    "shared:test": "npm test --workspace shared",
+    "test:all": "CI=true react-scripts test --watchAll=false && npm run shared:test && npm run server:test"
   },
   "eslintConfig": {
     "extends": [
@@ -39,5 +46,8 @@
       "last 1 firefox version",
       "last 1 safari version"
     ]
+  },
+  "devDependencies": {
+    "@testing-library/react": "^14.3.1"
   }
-}
+}

public/index.html

@@ -10,6 +10,9 @@
     />
     <link rel="apple-touch-icon" href="%PUBLIC_URL%/logo192.png" />
     <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
+    <link rel="preconnect" href="https://fonts.googleapis.com">
+    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
+    <link href="https://fonts.googleapis.com/css2?family=Cinzel:wght@400;600;700;900&family=Alegreya+Sans:ital,wght@0,400;0,500;0,700;1,400&display=swap" rel="stylesheet">
     <title>TTRPG Initiative Tracker</title>
   </head>
   <body>

scripts/README.md

@@ -0,0 +1,35 @@
+# scripts/
+
+Dev orchestration + manual demo tool. NOT test.
+
+## dev-start.sh / dev-stop.sh
+
+Local dev stack: backend (:4001, sqlite) + frontend (:3999, server mode).
+One command. Writes env vars for you. Logs to `tmp/server.log`, `tmp/fe.log`.
+
+```bash
+./scripts/dev-start.sh   # start (idempotent: leaves running ports as-is)
+./scripts/dev-stop.sh    # stop both
+```
+
+## replay-combat.js
+
+Live backend demo. Drives full combat via server adapter (same contract as App).
+Player display live-updates. Watch UI react to state changes.
+
+```bash
+# start backend + frontend first (see docs/DEVELOPMENT.md)
+node scripts/replay-combat.js [rounds] [delayMs]
+# defaults: 100 rounds, 200ms/step
+```
+
+Coverage per round: damage, heal, all 22 conditions, toggleActive,
+removeParticipant, addParticipant (reinforcements), updateParticipant,
+pause/resume, reorderParticipants, endEncounter. Revives dead each round
+to sustain full round count.
+
+## See also
+
+- `tests/audit/` — exploratory bug-finders (manual run, non-deterministic)
+- `{shared,server,src}/tests/` — jest unit/integration/characterization
+- `scratch/` — gitignored throwaway

scripts/analyze-turns.js

@@ -0,0 +1,315 @@
+// scripts/analyze-turns.js
+// Ingest replay-combat.js stdout (or any text matching its format), reconstruct
+// rounds, report real skips + double-acts. Deterministic — no eyeballing.
+//
+// Usage:
+//   node scripts/analyze-turns.js [path]        # analyze a saved log file
+//   node scripts/replay-combat.js 100 100 | node scripts/analyze-turns.js
+//   cat /tmp/replay.log | node scripts/analyze-turns.js
+//
+// Skip = participant active for WHOLE round (never deactivated/removed mid-round
+// before their slot, never added mid-round) but never appeared as a turn actor.
+// Double-act = same participant takes 2+ turns in one round.
+//
+// FEAT-2 (structured turn snapshot in app logs) will let this ingest live app
+// logs too, not just replay stdout. Format-agnostic core lives in parseReplay().
+
+'use strict';
+
+const fs = require('fs');
+
+// ---------- parsing ----------
+
+const TURN_RE = /^\s*turn\s+(\d+)\s+\(round\s+(\d+)\):\s+(.+?)(?:\s*\|\s*order=\[(.*)\](?:\s*cur=.*)?)?\s*$/;
+const DEACTIVATE_RE = /^\s*\[(?:deactivate)\s+(.+?)\]\s*$/;
+const REACTIVATE_RE = /^\s*\[(?:revive-reactivate|reactivate)\s+(.+?)\]\s*$/;
+const ADD_RE = /^\s*\[(?:add)\s+(.+?)\]\s*$/;
+const REMOVE_RE = /^\s*\[(?:remove dead|remove)\s+(.+?)\]\s*$/;
+const PAUSE_RE = /^\s*\[pause\]\s*$/;
+const RESUME_RE = /^\s*\[resume\]\s*$/;
+const ROUND_COMPLETE_RE = /^\s*---\s*round\s+(\d+)\s+(?:complete|starting)/;
+const FIRST_RE = /^combat started:\s+round\s+\d+,\s+first=(.+?)\s*$/;
+const REORDER_RE = /^\s*\[reorder\s+(.+?)→before\s+(.+?)\]\s*$/;
+const POINTER_RE = /^\s*\[pointer\s+(.+?)→(.+?)( wrap)?\]\s*$/;
+
+function parseLine(line) {
+  if (TURN_RE.test(line)) {
+    const m = line.match(TURN_RE);
+    const orderStr = m[4] || '';
+    // parse Name:init pairs
+    const order = orderStr.split(',').map(s => s.trim()).filter(Boolean).map(pair => {
+      const [name, init] = pair.split(':');
+      return { name: name.trim(), init: init !== undefined ? +init : null };
+    });
+    return { kind: 'turn', turn: +m[1], round: +m[2], actor: m[3].trim(), order };
+  }
+  if (FIRST_RE.test(line)) {
+    const m = line.match(FIRST_RE);
+    return { kind: 'turn', turn: 0, round: 1, actor: m[1].trim() };
+  }
+  if (DEACTIVATE_RE.test(line)) return { kind: 'deactivate', name: line.match(DEACTIVATE_RE)[1].trim() };
+  if (REACTIVATE_RE.test(line)) return { kind: 'reactivate', name: line.match(REACTIVATE_RE)[1].trim() };
+  if (ADD_RE.test(line)) return { kind: 'add', name: line.match(ADD_RE)[1].trim() };
+  if (REMOVE_RE.test(line)) return { kind: 'remove', name: line.match(REMOVE_RE)[1].trim() };
+  if (PAUSE_RE.test(line)) return { kind: 'pause' };
+  if (RESUME_RE.test(line)) return { kind: 'resume' };
+  if (POINTER_RE.test(line)) {
+    const m = line.match(POINTER_RE);
+    return { kind: 'pointer', from: m[1].trim(), to: m[2].trim(), wrap: m[3] === ' wrap' };
+  }
+  if (REORDER_RE.test(line)) {
+    const m = line.match(REORDER_RE);
+    return { kind: 'reorder', dragged: m[1].trim(), target: m[2].trim() };
+  }
+  if (ROUND_COMPLETE_RE.test(line)) return { kind: 'round-complete', round: +line.match(ROUND_COMPLETE_RE)[1] };
+  return null;
+}
+
+// ---------- reconstruction ----------
+
+// Build per-round timeline: round -> { turns: [actor], mutations: [{stepIdx,...}] }
+// Then compute skips + double-acts.
+function reconstruct(events) {
+  // global state: active set by name. Start populated lazily from first turn.
+  const active = new Set();
+  const rounds = new Map(); // round -> { turns: [name], events: [{...}] }
+  let curRound = 1;
+  let sawFirstTurn = false;
+
+  for (const ev of events) {
+    if (ev.kind === 'turn') {
+      sawFirstTurn = true;
+      curRound = ev.round;
+      if (!rounds.has(curRound)) rounds.set(curRound, { turns: [], events: [], complete: false });
+      const r = rounds.get(curRound);
+      r.turns.push(ev.actor);
+      r.events.push({ ...ev, idx: r.events.length });
+      if (!active.has(ev.actor)) active.add(ev.actor); // first sighting = active
+    } else if (ev.kind === 'deactivate') {
+      active.delete(ev.name);
+      const r = rounds.get(curRound) || rounds.set(curRound, { turns: [], events: [], complete: false }).get(curRound);
+      r.events.push({ ...ev, idx: r.events.length });
+    } else if (ev.kind === 'reactivate' || ev.kind === 'add') {
+      active.add(ev.name);
+      const r = rounds.get(curRound) || rounds.set(curRound, { turns: [], events: [], complete: false }).get(curRound);
+      r.events.push({ ...ev, idx: r.events.length });
+    } else if (ev.kind === 'remove') {
+      active.delete(ev.name);
+      const r = rounds.get(curRound) || rounds.set(curRound, { turns: [], events: [], complete: false }).get(curRound);
+      r.events.push({ ...ev, idx: r.events.length });
+    } else if (ev.kind === 'pointer') {
+      // wrap pointer advances to next round — credit there.
+      if (ev.wrap) curRound += 1;
+      const r = rounds.get(curRound) || rounds.set(curRound, { turns: [], events: [], complete: false }).get(curRound);
+      r.events.push({ ...ev, idx: r.events.length });
+    } else if (ev.kind === 'reorder') {
+      const r = rounds.get(curRound) || rounds.set(curRound, { turns: [], events: [], complete: false }).get(curRound);
+      r.events.push({ ...ev, idx: r.events.length });
+    } else if (ev.kind === 'round-complete') {
+      if (rounds.has(ev.round)) rounds.get(ev.round).complete = true;
+    }
+    // pause/resume: rotation-affecting but no roster change; tracked in events
+    else if (ev.kind === 'pause' || ev.kind === 'resume') {
+      const r = rounds.get(curRound) || rounds.set(curRound, { turns: [], events: [], complete: false }).get(curRound);
+      r.events.push({ ...ev, idx: r.events.length });
+    }
+  }
+  return rounds;
+}
+
+// For each round, recompute active-at-start and acted, then find real skips.
+function analyze(rounds) {
+  const report = [];
+  for (const [roundN, r] of [...rounds.entries()].sort((a, b) => a[0] - b[0])) {
+    // Replay stdout doesn't dump roster, so infer "active at round start":
+    // walk events IN ORDER, snapshot active set at first turn of this round.
+    // We replay from a clean per-round pass using a carry-over active set.
+    report.push(analyzeRound(roundN, r));
+  }
+  return report;
+}
+
+// Re-run per-round with active-set carry-over across rounds (module scope).
+function analyzeRounds(rounds) {
+  // Carry active set + current-name forward round to round.
+  let activeCarry = new Set();
+  let currentCarry = null;
+  const reports = [];
+  const sortedRounds = [...rounds.entries()].sort((a, b) => a[0] - b[0]);
+  for (const [roundN, r] of sortedRounds) {
+    if (!r.complete) continue; // incomplete final round — can't judge skips
+    if (roundN === 1) { activeCarry = new Set(); currentCarry = null; }
+    const result = analyzeRoundWithCarry(roundN, r, activeCarry, currentCarry);
+    reports.push(result.report);
+    activeCarry = result.activeAfter;
+    currentCarry = result.currentAfter;
+  }
+  return reports;
+}
+
+// When current participant is deactivated/removed, code advances current to
+// next active. That target gets the turn pointer = acts. Parser can't see
+// roster/order from stdout, so on deact-current the NEXT turn actor is the
+// advance target and is credited an extra "pointer turn" (not a logged turn).
+function analyzeRoundWithCarry(roundN, r, activeAtStart, currentAtStart) {
+  // activeAtStart: Set copy. Mutations during round adjust a working copy.
+  const active = new Set(activeAtStart);
+  const activeWholeRound = new Set(activeAtStart); // participants never toggled off/removed
+  const addedThisRound = new Set();
+  const turns = []; // ordered actor names (logged)
+  const pointerTurns = new Set(); // names that got the turn pointer this round
+  let current = currentAtStart; // current participant name (carry)
+
+  for (const ev of r.events) {
+    if (ev.kind === 'turn') {
+      turns.push(ev.actor);
+      pointerTurns.add(ev.actor);
+      if (!active.has(ev.actor)) active.add(ev.actor); // first-ever sighting
+      current = ev.actor;
+    } else if (ev.kind === 'pointer') {
+      // mutation advanced current pointer: ev.to now holds it = got the turn.
+      // Credit ev.to. Update tracking.
+      pointerTurns.add(ev.to);
+      current = ev.to;
+    } else if (ev.kind === 'deactivate' || ev.kind === 'remove') {
+      // deact/REMOVE of current → code auto-advances (emitted as pointer line).
+      // Disqualify from whole-round (roster mutation = not "whole round").
+      activeWholeRound.delete(ev.name);
+      active.delete(ev.name);
+    } else if (ev.kind === 'reactivate' || ev.kind === 'add') {
+      activeWholeRound.delete(ev.name);
+      active.add(ev.name);
+    }
+  }
+
+  // acted = names that took a turn OR got pointer via mutation-advance
+  // (deact/remove of current advances to target — that target acts).
+  // Pointer lines from replay tell us the target explicitly.
+  const acted = new Set([...turns, ...pointerTurns]);
+
+  // double-acts: logged turns with count > 1 (pointer-credits excluded —
+  // a deact-advance target acting once via pointer then once via nextTurn
+  // is correct, not a bug).
+  const counts = {};
+  for (const n of turns) counts[n] = (counts[n] || 0) + 1;
+  const doubleActs = Object.entries(counts).filter(([_, c]) => c > 1).map(([n, c]) => ({ name: n, count: c }));
+
+  // real skip: active for WHOLE round (no roster mutation) AND never got
+  // turn/pointer. Mutations disqualify from whole-round already.
+  const realSkips = [...activeWholeRound].filter(n => !acted.has(n));
+
+  return {
+    report: {
+      round: roundN,
+      turnCount: turns.length,
+      uniqueActors: acted.size,
+      realSkips,
+      doubleActs,
+      turns,
+    },
+    activeAfter: active,
+    currentAfter: current,
+  };
+}
+
+// ---------- order-shift detection ----------
+// Compare order+init between consecutive turn lines. Flag shifts NOT explained
+// by: logged reorder, add/remove (roster change), or initiative change.
+// DM drag-reorder = legit (logged reorder line). Phantom shifts = display/rotation
+// divergence bug (invariant: display === turnOrderIds === nextTurn).
+function detectOrderShifts(events) {
+  const shifts = [];
+  let prev = null;
+  let prevTurnNo = null;
+  // mutations since last turn (reorder/add/remove/reactivate/pointer)
+  let pending = [];
+  let initMap = {}; // name -> last known initiative
+
+  for (const ev of events) {
+    if (ev.kind === 'turn' && ev.order && ev.order.length) {
+      const curNames = ev.order.map(o => o.name);
+      const curInits = {};
+      ev.order.forEach(o => { curInits[o.name] = o.init; });
+
+      if (prev) {
+        const sameRoster = prev.length === curNames.length &&
+          prev.every((n, i) => n === curNames[i]);
+        if (!sameRoster) {
+          // roster change (add/remove) — skip, expected order shift
+        } else {
+          // same roster, different order → explainable by reorder OR init change?
+          const orderChanged = JSON.stringify(prev) !== JSON.stringify(curNames);
+          const initChanged = ev.order.some(o => initMap[o.name] !== null && initMap[o.name] !== undefined && initMap[o.name] !== o.init);
+          const hasReorder = pending.some(p => p.kind === 'reorder');
+          if (orderChanged && !hasReorder && !initChanged) {
+            shifts.push({ turn: ev.turn, from: prev, to: curNames, reason: 'no logged reorder/init change' });
+          }
+        }
+      }
+      prev = curNames;
+      curInits && Object.keys(curInits).forEach(k => { initMap[k] = curInits[k]; });
+      pending = [];
+      prevTurnNo = ev.turn;
+    } else if (ev.kind === 'reorder' || ev.kind === 'add' || ev.kind === 'remove' ||
+               ev.kind === 'reactivate' || ev.kind === 'pointer') {
+      pending.push(ev);
+    }
+  }
+  return shifts;
+}
+
+// ---------- CLI ----------
+
+function readInput() {
+  const arg = process.argv[2];
+  if (arg) return fs.readFileSync(arg, 'utf8');
+  // stdin
+  return fs.readFileSync(0, 'utf8');
+}
+
+function main() {
+  const text = readInput();
+  const lines = text.split('\n');
+  const events = lines.map(parseLine).filter(Boolean);
+  const rounds = reconstruct(events);
+  const reports = analyzeRounds(rounds);
+
+  let totalSkips = 0;
+  let totalDoubles = 0;
+  const problemRounds = [];
+
+  for (const rep of reports) {
+    const hasIssue = rep.realSkips.length > 0 || rep.doubleActs.length > 0;
+    if (hasIssue) problemRounds.push(rep);
+    totalSkips += rep.realSkips.length;
+    totalDoubles += rep.doubleActs.length;
+  }
+
+  for (const rep of problemRounds) {
+    console.log(`R${rep.round}: turns=${rep.turnCount} unique=${rep.uniqueActors}`);
+    if (rep.realSkips.length) console.log(`  REAL SKIPS: ${rep.realSkips.join(', ')}`);
+    if (rep.doubleActs.length) console.log(`  DOUBLE-ACTS: ${rep.doubleActs.map(d => `${d.name}(${d.count}x)`).join(', ')}`);
+    console.log(`  sequence: ${rep.turns.join(' -> ')}`);
+  }
+
+  // order-shift detection: flag unexplained display/rotation divergence
+  const shifts = detectOrderShifts(events);
+  if (shifts.length) {
+    console.log(`\n--- order shifts (${shifts.length}) ---`);
+    for (const s of shifts.slice(0, 10)) {
+      console.log(`  turn ${s.turn}: [${s.from.join(',')}] → [${s.to.join(',')}] (${s.reason})`);
+    }
+    if (shifts.length > 10) console.log(`  ... +${shifts.length - 10} more`);
+  }
+
+  console.log(`\n=== ${reports.length} rounds analyzed ===`);
+  console.log(`real skips: ${totalSkips}`);
+  console.log(`double-acts: ${totalDoubles}`);
+  console.log(`order shifts: ${shifts.length}`);
+  const clean = totalSkips === 0 && totalDoubles === 0 && shifts.length === 0;
+  console.log(clean ? 'CLEAN — no rotation bugs' : 'ISSUES FOUND');
+
+  process.exit(clean ? 0 : 1);
+}
+
+main();

scripts/dev-start.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+# Start local dev stack: node backend (sqlite) + react frontend, server storage mode.
+# Usage: ./scripts/dev-start.sh
+# Stop:  ./scripts/dev-stop.sh
+set -euo pipefail
+cd "$(dirname "$0")/.."
+mkdir -p tmp data
+
+# kill anything on the ports (zombies)
+for port in 3999 4001; do
+  pids=$(lsof -ti :$port 2>/dev/null || true)
+  if [ -n "$pids" ]; then
+    echo "port $port in use by: $pids — leaving as-is."
+    echo "  (run ./scripts/dev-stop.sh first to restart clean)"
+  fi
+done
+
+# backend: better-sqlite3, :4001
+if ! lsof -ti :4001 >/dev/null 2>&1; then
+  echo "starting backend :4001..."
+  DB_PATH=$(pwd)/data/tracker.sqlite PORT=4001 \
+    nohup npm run server:dev > tmp/server.log 2>&1 &
+  echo $! > tmp/server.pid
+else
+  echo "backend already on :4001"
+fi
+
+# frontend: server storage, :3999
+if ! lsof -ti :3999 >/dev/null 2>&1; then
+  echo "starting frontend :3999..."
+  REACT_APP_STORAGE=server \
+  REACT_APP_BACKEND_URL=http://127.0.0.1:4001 \
+  REACT_APP_BACKEND_REALTIME_URL=ws://127.0.0.1:4001/ws \
+  BROWSER=none PORT=3999 \
+    nohup npm start > tmp/fe.log 2>&1 &
+  echo $! > tmp/fe.pid
+else
+  echo "frontend already on :3999"
+fi
+
+# wait for ports to listen
+echo "waiting for ports..."
+for port in 4001 3999; do
+  for i in {1..30}; do
+    lsof -ti :$port >/dev/null 2>&1 && break
+    sleep 1
+  done
+done
+
+echo ""
+echo "backend  : http://127.0.0.1:4001   (curl http://127.0.0.1:4001/health)"
+echo "frontend : http://127.0.0.1:3999   (admin /  player /display)"
+echo "logs     : tmp/server.log tmp/fe.log"
+echo "stop     : ./scripts/dev-stop.sh"

scripts/dev-stop.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+# Stop local dev stack. Usage: ./scripts/dev-stop.sh
+set -uo pipefail
+cd "$(dirname "$0")/.."
+
+stopped=0
+for port in 3999 4001; do
+  pids=$(lsof -ti :$port 2>/dev/null || true)
+  if [ -n "$pids" ]; then
+    echo "stopping :$port (pid: $pids)"
+    kill $pids 2>/dev/null || true
+    stopped=1
+  fi
+done
+
+# also kill recorded pids
+for f in tmp/server.pid tmp/fe.pid; do
+  if [ -f "$f" ]; then
+    pid=$(cat "$f")
+    kill "$pid" 2>/dev/null || true
+    rm -f "$f"
+  fi
+done
+
+# node --watch spawns children — sweep by port pattern
+pids=$(pgrep -f "node --watch index.js|react-scripts start" 2>/dev/null || true)
+if [ -n "$pids" ]; then
+  echo "sweeping node dev procs: $pids"
+  kill $pids 2>/dev/null || true
+fi
+
+if [ "$stopped" = "0" ]; then
+  echo "nothing running."
+fi
+echo "stopped."

scripts/replay-combat.js

@@ -0,0 +1,379 @@
+// scripts/replay-combat.js
+// Drive a full combat through the LIVE backend via the ws storage adapter
+// (same contract boundary as the App), so the player display window
+// (subscribed via WS) live-updates as combat progresses.
+// Uses shared/turn.js for all turn logic (same model as the UI).
+//
+// Coverage goals (rotate across rounds):
+//   - nextTurn (every turn)
+//   - applyHpChange damage + heal (varying magnitude)
+//   - toggleCondition (all CONDITIONS at least once)
+//   - toggleParticipantActive (mark inactive, later reactivate)
+//   - deathSave (when a PC reaches 0 HP)
+//   - addParticipant (reinforcements drop in)
+//   - removeParticipant (dead monsters hauled off)
+//   - updateParticipant (edit fields mid-combat)
+//   - togglePause / resume
+//   - reorderParticipants (initiative reorder)
+//   - endEncounter (cleanup)
+//
+// Run: node scripts/replay-combat.js [rounds] [delayMs]
+//   rounds default 100, delayMs default 200
+
+'use strict';
+
+const shared = require('../shared');
+const {
+  buildCharacterParticipant, buildMonsterParticipant,
+  startEncounter, nextTurn, togglePause,
+  addParticipant, updateParticipant, removeParticipant,
+  toggleParticipantActive, applyHpChange, deathSave,
+  toggleCondition, reorderParticipants, endEncounter,
+} = shared;
+const { createServerStorage } = require('../src/storage/server');
+
+const BACKEND = process.env.BACKEND_URL || 'http://127.0.0.1:4001';
+const WS_URL = process.env.BACKEND_REALTIME_URL || BACKEND.replace(/^http/, 'ws') + '/ws';
+const ROUNDS = parseInt(process.argv[2], 10) || 100;
+const DELAY = parseInt(process.argv[3], 10) || 200;
+
+const APP_ID = process.env.REACT_APP_TRACKER_APP_ID || 'ttrpg-initiative-tracker-default';
+const PUB = `artifacts/${APP_ID}/public/data`;
+// Mirror App.js getPath. Adapter takes these; norm() strips prefix.
+const getPath = {
+  campaigns: () => `${PUB}/campaigns`,
+  campaign: (id) => `${PUB}/campaigns/${id}`,
+  encounters: (cid) => `${PUB}/campaigns/${cid}/encounters`,
+  encounter: (cid, eid) => `${PUB}/campaigns/${cid}/encounters/${eid}`,
+  activeDisplay: () => `${PUB}/activeDisplay/status`,
+};
+
+const sleep = (ms) => new Promise(r => setTimeout(r, ms));
+
+// Use the ADAPTER as the contract boundary (same as App). No raw REST.
+const storage = createServerStorage({ baseUrl: BACKEND, realtimeUrl: WS_URL });
+
+// Mirror App.js CONDITIONS so we exercise all of them.
+const CONDITIONS = [
+  'alchemist_fire', 'bardic_inspiration', 'blinded', 'charmed', 'deafened',
+  'exhaustion', 'frightened', 'grappled', 'grazed', 'incapacitated',
+  'invisible', 'paralyzed', 'petrified', 'poisoned', 'prone', 'restrained',
+  'sapped', 'shield', 'slowed', 'stunned', 'unconscious', 'vexed',
+];
+// Custom (freeform) condition ids — DM-added strings. toggleCondition must
+// accept ANY string (UI custom-condition contract). Exercise both paths.
+const CUSTOM_CONDITIONS = ['hexed', 'rager', 'marked_for_death', '🛡️blessed'];
+
+async function patch(encounterPath, enc, result, label) {
+  if (!result || !result.patch) { if (label) console.log(`  (${label}: no-op)`); return enc; }
+  await storage.updateDoc(encounterPath, result.patch);
+  if (label) console.log(`  [${label}]`);
+  // emit pointer-advance line when a MUTATION changes currentTurnParticipantId.
+  // nextTurn passes label=null — it's a normal advance, already logged via
+  // the turn line. Emitting pointer for it double-counts.
+  const oldCur = enc.currentTurnParticipantId;
+  const oldRound = enc.round;
+  const newEnc = { ...enc, ...result.patch };
+  const newCur = newEnc.currentTurnParticipantId;
+  const newRound = newEnc.round;
+  if (label && oldCur && newCur && oldCur !== newCur) {
+    const oldName = enc.participants.find(p => p.id === oldCur)?.name || oldCur;
+    const newName = newEnc.participants.find(p => p.id === newCur)?.name || newCur;
+    const wrap = oldRound !== newRound ? ' wrap' : '';
+    console.log(`  [pointer ${oldName}→${newName}${wrap}]`);
+  }
+  return newEnc;
+}
+
+function pick(arr) { return arr[Math.floor(Math.random() * arr.length)]; }
+
+async function main() {
+  console.log(`replay-combat: ${ROUNDS} rounds, ${DELAY}ms/step, backend=${BACKEND}`);
+
+  const campaignId = crypto.randomUUID();
+  const encounterId = crypto.randomUUID();
+
+  await storage.setDoc(getPath.campaign(campaignId), {
+    name: `Replay Campaign (${new Date().toLocaleString('en-US', { hour12: false })})`,
+    playerDisplayBackgroundUrl: '',
+    ownerId: 'replay',
+    createdAt: new Date().toISOString(),
+    players: [
+      { id: 'c1', name: 'Fighter', defaultMaxHp: 200, defaultInitMod: 2 },
+      { id: 'c2', name: 'Cleric', defaultMaxHp: 180, defaultInitMod: 1 },
+      { id: 'c3', name: 'Rogue', defaultMaxHp: 160, defaultInitMod: 3 },
+    ],
+  });
+
+  const charSpecs = [
+    { id: 'c1', name: 'Fighter', defaultMaxHp: 200, defaultInitMod: 2 },
+    { id: 'c2', name: 'Cleric', defaultMaxHp: 180, defaultInitMod: 1 },
+    { id: 'c3', name: 'Rogue', defaultMaxHp: 160, defaultInitMod: 3 },
+  ];
+  const monsterSpecs = [
+    { name: 'Goblin1', maxHp: 100, initMod: 2 },
+    { name: 'Goblin2', maxHp: 100, initMod: 2 },
+    { name: 'OrcBoss', maxHp: 500, initMod: 1 },
+    { name: 'Wolf', maxHp: 120, initMod: 3 },
+    { name: 'Merchant', maxHp: 150, initMod: 0, isNpc: true },
+  ];
+
+  const participants = [
+    ...charSpecs.map(c => buildCharacterParticipant(c).participant),
+    ...monsterSpecs.map(m => buildMonsterParticipant(m).participant),
+  ];
+
+  await storage.setDoc(getPath.encounter(campaignId, encounterId), {
+    name: `Big Boss Replay (${new Date().toLocaleString('en-US', { hour12: false })})`,
+    campaignId,
+    createdAt: new Date().toISOString(),
+    participants,
+    round: 0,
+    currentTurnParticipantId: null,
+    isStarted: false,
+    isPaused: false,
+    turnOrderIds: [],
+  });
+
+  console.log(`created: campaign=${campaignId} encounter=${encounterId} participants=${participants.length}`);
+
+  await storage.setDoc(getPath.activeDisplay(), {
+    activeCampaignId: campaignId,
+    activeEncounterId: encounterId,
+    hidePlayerHp: false,
+  });
+  await sleep(800);
+
+  const encounterPath = getPath.encounter(campaignId, encounterId);
+  const activeDisplayPath = getPath.activeDisplay();
+
+  // start
+  let enc = await storage.getDoc(encounterPath);
+  enc = await patch(encounterPath, enc, startEncounter(enc), 'startEncounter');
+  console.log(`combat started: round ${enc.round}, first=${firstActiveName(enc)}`);
+  await sleep(DELAY);
+
+  let totalTurns = 0;
+  const condQueue = [...CONDITIONS, ...CUSTOM_CONDITIONS].sort(() => Math.random() - 0.5);
+  let reinforcementsAdded = 0;
+  let lastPaused = false;
+  let lastReorder = 0;
+
+  for (let roundN = 1; roundN <= ROUNDS; roundN++) {
+    console.log(`--- round ${roundN} starting ---`);
+    // advance initiative until round counter ticks (full cycle done).
+    const cap = (enc.participants.length + 2) * 2;
+    let guard = 0;
+    while (enc.round < roundN + 1 && guard < cap) {
+      // NOTE: do NOT getDoc here — async re-fetch can return stale state and
+      // cause nextTurn to compute off pre-mutation data (double-acts/skips).
+      // Trust the local enc returned by patch (sync spread of updateDoc).
+
+      // 9. resume if paused: must happen BEFORE nextTurn or it throws.
+      if (lastPaused) {
+        enc = await patch(encounterPath, enc, togglePause(enc), 'resume');
+        lastPaused = false;
+      }
+
+      let t;
+      try { t = nextTurn(enc); } catch (e) { console.log(`  nextTurn err: ${e.message}`); break; }
+      enc = await patch(encounterPath, enc, t, null);
+      totalTurns++;
+      const actorName = firstActiveName(enc);
+      const actor = currentParticipant(enc);
+
+      // Dump turn line with order AND initiative (DM drag may reorder without
+      // changing init — log both so parser can flag unexplained shifts).
+      const ordStr = enc.turnOrderIds.map(id => {
+        const p = enc.participants.find(x => x.id === id);
+        return p ? `${p.name}:${p.initiative}` : id;
+      }).join(',');
+      // Also dump participants[] order (display source). Diverge from order = sync bug.
+      const pStr = enc.participants.map(p => `${p.name}:${p.initiative}`).join(',');
+      console.log(`  turn ${totalTurns} (round ${enc.round}): ${actorName} | order=[${ordStr}] parts=[${pStr}] cur=${enc.currentTurnParticipantId}`);
+
+      // 1. damage: actor hits a random living, active target.
+      if (actor) {
+        const foes = enc.participants.filter(
+          p => p.id !== actor.id && p.currentHp > 0 && p.isActive !== false && !p.name.startsWith('Dead')
+        );
+        if (foes.length > 0) {
+          const tgt = pick(foes);
+          const dmg = 1 + Math.floor(Math.random() * 5); // 1-5
+          const h = applyHpChange(enc, tgt.id, 'damage', dmg);
+          if (h.patch) {
+            await storage.updateDoc(encounterPath, h.patch);
+            enc = { ...enc, ...h.patch };
+            console.log(`    ${actorName} → ${tgt.name} (-${dmg}, hp=${tgt.currentHp - dmg})`);
+          }
+        }
+      }
+
+      // 2. heal: Cleric (when active) heals lowest-HP ally every other turn.
+      if (actor && actor.name === 'Cleric' && totalTurns % 2 === 0) {
+        const wounded = enc.participants
+          .filter(p => p.currentHp > 0 && p.currentHp < p.maxHp && p.isActive !== false)
+          .sort((a, b) => (a.currentHp / a.maxHp) - (b.currentHp / b.maxHp));
+        if (wounded.length > 0) {
+          const tgt = wounded[0];
+          const amt = 2 + Math.floor(Math.random() * 5); // 2-6
+          const h = applyHpChange(enc, tgt.id, 'heal', amt);
+          if (h.patch) {
+            await storage.updateDoc(encounterPath, h.patch);
+            enc = { ...enc, ...h.patch };
+            console.log(`    Cleric heal → ${tgt.name} (+${amt}, hp=${tgt.currentHp + amt})`);
+          }
+        }
+      }
+
+      // 3. conditions: toggle a queued condition off some participant each turn.
+      if (condQueue.length > 0) {
+        const cond = condQueue[0];
+        const living = enc.participants.filter(p => p.currentHp > 0 && p.isActive !== false);
+        if (living.length > 0) {
+          const tgt = pick(living);
+          try {
+            const c = toggleCondition(enc, tgt.id, cond);
+            enc = await patch(encounterPath, enc, c, `condition ${cond} on ${tgt.name}`);
+            condQueue.shift();
+          } catch (e) { console.log(`    condition ${cond} err: ${e.message}`); condQueue.shift(); }
+        }
+      } else if (totalTurns % 6 === 0) {
+        // second pass: toggle a random condition on random participant (add/remove).
+        const living = enc.participants.filter(p => p.currentHp > 0 && p.isActive !== false);
+        if (living.length > 0) {
+          const tgt = pick(living);
+          const cond = pick([...CONDITIONS, ...CUSTOM_CONDITIONS]);
+          try {
+            const c = toggleCondition(enc, tgt.id, cond);
+            enc = await patch(encounterPath, enc, c, `condition ${cond} on ${tgt.name}`);
+          } catch (e) { /* ignore */ }
+        }
+      }
+
+      // 4. toggleParticipantActive: randomly mark someone inactive, or reactivate.
+      if (totalTurns % 9 === 0) {
+        const living = enc.participants.filter(p => p.currentHp > 0);
+        if (living.length > 0) {
+          const tgt = pick(living);
+          try {
+            const r = toggleParticipantActive(enc, tgt.id);
+            enc = await patch(encounterPath, enc, r, `${tgt.isActive === false ? 'reactivate' : 'deactivate'} ${tgt.name}`);
+          } catch (e) { /* ignore */ }
+        }
+      }
+
+      // 5. deathSave: when a PC is at 0 HP on their turn, attempt a save.
+      if (actor && actor.currentHp <= 0 && !actor.isNpc && actor.name !== actor.name.startsWith('Monster')) {
+        try {
+          const ds = deathSave(enc, actor.id, 1);
+          enc = await patch(encounterPath, enc, ds, `deathSave ${actor.name} (+1 success)`);
+        } catch (e) { /* ignore */ }
+      }
+
+      // 6. removeParticipant: dead monsters hauled off (every ~5 turns).
+      if (totalTurns % 5 === 0) {
+        const dead = enc.participants.find(p => (p.isDying || p.currentHp <= 0) && (p.isNpc || p.name.startsWith('Goblin') || p.name === 'OrcBoss' || p.name === 'Wolf'));
+        if (dead) {
+          try {
+            const r = removeParticipant(enc, dead.id);
+            enc = await patch(encounterPath, enc, r, `remove dead ${dead.name}`);
+          } catch (e) { /* ignore */ }
+        }
+      }
+
+      // 7. addParticipant (reinforcements): every 10 turns a new monster joins.
+      if (totalTurns % 10 === 0 && reinforcementsAdded < 4) {
+        const spec = pick([
+          { name: `Reinforce${reinforcementsAdded + 1}`, maxHp: 120, initMod: 1 },
+          { name: `Summon${reinforcementsAdded + 1}`, maxHp: 80, initMod: 4 },
+        ]);
+        try {
+          const built = buildMonsterParticipant(spec).participant;
+          const r = addParticipant(enc, built);
+          enc = await patch(encounterPath, enc, r, `add ${spec.name}`);
+          reinforcementsAdded++;
+        } catch (e) { /* ignore */ }
+      }
+
+      // 8. updateParticipant: every 7 turns, edit a field on someone (e.g. temp AC).
+      if (totalTurns % 7 === 0) {
+        const living = enc.participants.filter(p => p.currentHp > 0);
+        if (living.length > 0) {
+          const tgt = pick(living);
+          try {
+            const r = updateParticipant(enc, tgt.id, { notes: `edited@turn${totalTurns}` });
+            enc = await patch(encounterPath, enc, r, `edit ${tgt.name} notes`);
+          } catch (e) { /* ignore */ }
+        }
+      }
+
+      // 9. togglePause: every 12 turns, pause (resumes next iteration via above).
+      if (totalTurns % 12 === 0 && !lastPaused) {
+        enc = await patch(encounterPath, enc, togglePause(enc), 'pause');
+        lastPaused = true;
+      }
+
+      // 10. reorderParticipants: every 8 turns, drag one past another (DM reorder).
+      // Pick two ADJACENT UPCOMING actors (both strictly after current pointer)
+      // and swap them. Avoids crossing current pointer — crossing it creates
+      // ambiguous "who acted this round" semantics (skip/double). Swapping two
+      // upcoming actors is always safe and still exercises reorder.
+      if (totalTurns % 8 === 0 && lastReorder !== totalTurns) {
+        const curIdx = enc.turnOrderIds.indexOf(enc.currentTurnParticipantId);
+        // upcoming = everyone after current in turn order (rest of this round)
+        const upcomingIds = enc.turnOrderIds.slice(curIdx + 1)
+          .filter(id => { const p = enc.participants.find(x => x.id === id); return p && p.currentHp > 0 && p.isActive !== false; });
+        // swap first adjacent upcoming pair (drag index1 before index0)
+        if (upcomingIds.length >= 2) {
+          const target = enc.participants.find(p => p.id === upcomingIds[0]);
+          const dragged = enc.participants.find(p => p.id === upcomingIds[1]);
+          try {
+            const r = reorderParticipants(enc, dragged.id, target.id);
+            enc = await patch(encounterPath, enc, r, `reorder ${dragged.name}→before ${target.name}`);
+            lastReorder = totalTurns;
+          } catch (e) { /* swap not allowed — skip this round */ }
+        }
+      }
+
+      await sleep(DELAY);
+      guard++;
+      if (!enc.isStarted) { console.log('combat auto-ended'); break; }
+    }
+    if (!enc.isStarted) { console.log('combat auto-ended'); break; }
+    const alive = enc.participants.filter(p => p.currentHp > 0).length;
+    // revive dead: heal to full + reactivate. Sustains combat for 100 rounds
+    // and exercises toggleActive reactivate + heal-from-zero path.
+    const dead = enc.participants.filter(p => p.currentHp <= 0 || p.isActive === false);
+    for (const d of dead) {
+      try {
+        if (d.isActive === false) {
+          enc = await patch(encounterPath, enc, toggleParticipantActive(enc, d.id), `revive-reactivate ${d.name}`);
+        }
+        const h = applyHpChange(enc, d.id, 'heal', d.maxHp);
+        enc = await patch(encounterPath, enc, h, `revive-heal ${d.name} →${d.maxHp}`);
+      } catch (e) { console.log(`    revive ${d.name} err: ${e.message}`); }
+    }
+  }
+
+  console.log(`replay: ${totalTurns} total turns across ${ROUNDS} rounds`);
+
+  // end
+  enc = await storage.getDoc(encounterPath);
+  if (enc.isStarted) enc = await patch(encounterPath, enc, endEncounter(enc), 'endEncounter');
+  await storage.updateDoc(activeDisplayPath, { activeCampaignId: null, activeEncounterId: null });
+  console.log('replay done');
+}
+
+function firstActiveName(enc) {
+  if (!enc.currentTurnParticipantId) return '(none)';
+  const p = currentParticipant(enc);
+  return p ? p.name : '(missing)';
+}
+
+function currentParticipant(enc) {
+  if (!enc.currentTurnParticipantId) return null;
+  return (enc.participants || []).find(x => x.id === enc.currentTurnParticipantId) || null;
+}
+
+main().catch(err => { console.error('replay failed:', err); process.exit(1); });

server/babel.config.js

@@ -0,0 +1,3 @@
+module.exports = {
+  presets: [['@babel/preset-env', { targets: { node: 'current' } }]],
+};

server/db.js

@@ -0,0 +1,110 @@
+// server/db.js — generic KV document store on SQLite.
+// Mirrors Firestore doc-tree model: every doc lives at a string path.
+// Collections are implicit = all docs whose parent path equals the collection path.
+//
+// Path examples (canonical, prefix already stripped by adapter):
+//   campaigns/{id}                       doc
+//   campaigns/{cid}/encounters/{eid}     doc
+//   campaigns/{cid}/encounters           collection (parent of encounter docs)
+//   activeDisplay/status                 doc
+//   logs/{id}                            doc
+//
+// No shape-specific tables. Data is opaque JSON. This is the firebase mirror:
+// the adapter (src/storage/server.js) is a thin passthrough, app logic unchanged.
+
+'use strict';
+
+const Database = require('better-sqlite3');
+const path = require('path');
+const fs = require('fs');
+
+const SCHEMA = `
+CREATE TABLE IF NOT EXISTS docs (
+  path TEXT PRIMARY KEY,
+  parent TEXT,
+  data TEXT NOT NULL,
+  updated_at INTEGER NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_docs_parent ON docs(parent);
+`;
+
+function openDb(dbPath) {
+  const dir = path.dirname(dbPath);
+  if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
+  const db = new Database(dbPath);
+  db.pragma('journal_mode = WAL');
+  db.exec(SCHEMA);
+  return db;
+}
+
+// parentOf('campaigns/abc/encounters/xyz') => 'campaigns/abc/encounters'
+// parentOf('campaigns') => null (root-level doc, no parent collection tracked)
+function parentOf(p) {
+  const i = p.lastIndexOf('/');
+  return i === -1 ? null : p.slice(0, i);
+}
+
+function makeStore(db, broadcast) {
+  const stmtGet = db.prepare('SELECT data FROM docs WHERE path = ?');
+  const stmtUpsert = db.prepare(`
+    INSERT INTO docs (path, parent, data, updated_at) VALUES (@path, @parent, @data, @ts)
+    ON CONFLICT(path) DO UPDATE SET data = @data, updated_at = @ts
+  `);
+  const stmtDelete = db.prepare('DELETE FROM docs WHERE path = ?');
+  const stmtColl = db.prepare('SELECT path, data FROM docs WHERE parent = ? ORDER BY path ASC');
+
+  function getDoc(p) {
+    const row = stmtGet.get(p);
+    return row ? JSON.parse(row.data) : null;
+  }
+
+  function setDoc(p, data) {
+    const ts = Date.now();
+    stmtUpsert.run({ path: p, parent: parentOf(p), data: JSON.stringify(data), ts });
+    if (broadcast) broadcast({ path: p, parent: parentOf(p) });
+    return data;
+  }
+
+  // shallow merge; if doc missing, patch becomes the doc (matches firebase updateDoc create-on-miss)
+  function updateDoc(p, patch) {
+    const existing = getDoc(p) || {};
+    const merged = { ...existing, ...patch };
+    setDoc(p, merged);
+    return merged;
+  }
+
+  function deleteDoc(p) {
+    stmtDelete.run(p);
+    if (broadcast) broadcast({ path: p, parent: parentOf(p), deleted: true });
+  }
+
+  function getCollection(collPath) {
+    return stmtColl.all(collPath).map(row => ({ id: row.path.split('/').pop(), path: row.path, ...JSON.parse(row.data) }));
+  }
+
+  function batchWrite(ops) {
+    const run = db.transaction((items) => {
+      const changed = [];
+      for (const op of items) {
+        if (op.type === 'set') {
+          setDoc(op.path, op.data);
+          changed.push({ path: op.path, parent: parentOf(op.path) });
+        } else if (op.type === 'delete') {
+          deleteDoc(op.path);
+          changed.push({ path: op.path, parent: parentOf(op.path), deleted: true });
+        } else if (op.type === 'update') {
+          updateDoc(op.path, op.data);
+          changed.push({ path: op.path, parent: parentOf(op.path) });
+        }
+      }
+      return changed;
+    });
+    const changed = run(ops);
+    if (broadcast) changed.forEach(c => broadcast(c));
+  }
+
+  return { getDoc, setDoc, updateDoc, deleteDoc, getCollection, batchWrite };
+}
+
+module.exports = { openDb, parentOf, makeStore };

server/index.js

@@ -0,0 +1,152 @@
+// server/index.js — generic KV document store over HTTP + WebSocket.
+// firebase mirror: doc-tree model. Thin REST, path-based WS push.
+// Adapter (src/storage/server.js) = passthrough, no shape translation.
+
+'use strict';
+
+const express = require('express');
+const cors = require('cors');
+const http = require('http');
+const crypto = require('crypto');
+const { WebSocketServer } = require('ws');
+const { openDb, makeStore } = require('./db');
+
+function createServer({ dbPath, port, corsOrigin } = {}) {
+  const db = openDb(dbPath || './data/tracker.sqlite');
+  const app = express();
+  app.use(cors({ origin: corsOrigin || '*' }));
+  app.use(express.json({ limit: '1mb' }));
+
+  // WS subscribers: path -> Set<ws>.
+  // Subscribers register a path (doc or collection). On change, notify:
+  //   - doc subscribers at the changed path
+  //   - collection subscribers at the changed doc's parent path
+  const docSubscribers = new Map();      // path -> Set<ws>
+  const collSubscribers = new Map();     // collPath -> Set<ws>
+
+  function addSub(map, key, ws) {
+    if (!map.has(key)) map.set(key, new Set());
+    map.get(key).add(ws);
+  }
+  function removeSub(map, key, ws) {
+    const set = map.get(key);
+    if (set) { set.delete(ws); if (set.size === 0) map.delete(key); }
+  }
+  function dropWs(ws) {
+    for (const [key, set] of docSubscribers) { set.delete(ws); if (set.size === 0) docSubscribers.delete(key); }
+    for (const [key, set] of collSubscribers) { set.delete(ws); if (set.size === 0) collSubscribers.delete(key); }
+  }
+
+  function broadcast(change) {
+    const payload = JSON.stringify({ type: 'change', change });
+    // doc subscriber at exact path
+    const docSet = docSubscribers.get(change.path);
+    if (docSet) [...docSet].forEach(ws => ws.readyState === ws.OPEN && ws.send(payload));
+    // collection subscribers at parent path (collection contains this doc)
+    if (change.parent) {
+      const collSet = collSubscribers.get(change.parent);
+      if (collSet) [...collSet].forEach(ws => ws.readyState === ws.OPEN && ws.send(payload));
+    }
+  }
+
+  const store = makeStore(db, broadcast);
+
+  // --- generic REST ---
+
+  app.get('/health', (req, res) => res.json({ ok: true }));
+
+  // GET /api/doc?path=campaigns/abc/encounters/xyz
+  app.get('/api/doc', (req, res) => {
+    const { path: p } = req.query;
+    if (!p) return res.status(400).json({ error: 'path required' });
+    res.json({ path: p, data: store.getDoc(p) });
+  });
+
+  // GET /api/collection?path=campaigns/abc/encounters
+  app.get('/api/collection', (req, res) => {
+    const { path: p } = req.query;
+    if (!p) return res.status(400).json({ error: 'path required' });
+    res.json(store.getCollection(p));
+  });
+
+  // PUT /api/doc  body: { path, data }   (replace)
+  app.put('/api/doc', (req, res) => {
+    const { path: p, data } = req.body || {};
+    if (!p) return res.status(400).json({ error: 'path required' });
+    res.json({ path: p, data: store.setDoc(p, data) });
+  });
+
+  // PATCH /api/doc  body: { path, patch }   (shallow merge, create-on-miss)
+  app.patch('/api/doc', (req, res) => {
+    const { path: p, patch } = req.body || {};
+    if (!p) return res.status(400).json({ error: 'path required' });
+    res.json({ path: p, data: store.updateDoc(p, patch) });
+  });
+
+  // DELETE /api/doc?path=...
+  app.delete('/api/doc', (req, res) => {
+    const { path: p } = req.query;
+    if (!p) return res.status(400).json({ error: 'path required' });
+    store.deleteDoc(p);
+    res.json({ ok: true });
+  });
+
+  // POST /api/collection  body: { path, data }  (addDoc: auto-id under collection)
+  app.post('/api/collection', (req, res) => {
+    const { path: collPath, data } = req.body || {};
+    if (!collPath) return res.status(400).json({ error: 'path required' });
+    const id = crypto.randomUUID();
+    const docPath = `${collPath}/${id}`;
+    res.json({ id, path: docPath, data: store.setDoc(docPath, data) });
+  });
+
+  // POST /api/batch  body: { ops: [{type:'set'|'update'|'delete', path, data?}] }
+  app.post('/api/batch', (req, res) => {
+    const { ops } = req.body || {};
+    if (!Array.isArray(ops)) return res.status(400).json({ error: 'ops array required' });
+    store.batchWrite(ops);
+    res.json({ ok: true });
+  });
+
+  // --- WebSocket: subscribe by path ---
+  const server = http.createServer(app);
+  const wss = new WebSocketServer({ server, path: '/ws' });
+
+  wss.on('connection', (ws) => {
+    ws.on('message', (raw) => {
+      let msg;
+      try { msg = JSON.parse(raw.toString()); } catch { ws.send(JSON.stringify({ type: 'error', error: 'bad json' })); return; }
+      if (msg.type === 'subscribe' && msg.path) {
+        if (msg.kind === 'collection') addSub(collSubscribers, msg.path, ws);
+        else addSub(docSubscribers, msg.path, ws);
+        ws.send(JSON.stringify({ type: 'subscribed', path: msg.path, kind: msg.kind || 'doc' }));
+      } else if (msg.type === 'unsubscribe' && msg.path) {
+        if (msg.kind === 'collection') removeSub(collSubscribers, msg.path, ws);
+        else removeSub(docSubscribers, msg.path, ws);
+      }
+    });
+    ws.on('close', () => dropWs(ws));
+    ws.on('error', () => {});
+  });
+
+  return {
+    app, server, wss, store, db,
+    close(done) {
+      wss.clients.forEach(c => { try { c.terminate(); } catch {} });
+      wss.close();
+      server.close(() => { db.close(); if (done) done(); });
+    },
+  };
+}
+
+// Boot standalone if run directly.
+if (require.main === module) {
+  const port = parseInt(process.env.PORT, 10) || 4001;
+  const dbPath = process.env.DB_PATH || './data/tracker.sqlite';
+  const { server } = createServer({ dbPath, port });
+  server.listen(port, () => {
+    console.log(`ttrpg backend listening on :${port} (db: ${dbPath})`);
+  });
+}
+
+module.exports = { createServer };

server/jest.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+  rootDir: '.',
+  testEnvironment: 'node',
+  testMatch: ['<rootDir>/tests/**/*.test.js'],
+  testTimeout: 10000,
+};

server/package.json

@@ -0,0 +1,24 @@
+{
+  "name": "@ttrpg/server",
+  "version": "0.1.0",
+  "private": true,
+  "description": "Self-hosted backend: Express + ws + better-sqlite3. Server-authoritative turn logic.",
+  "main": "index.js",
+  "scripts": {
+    "dev": "node --watch index.js",
+    "start": "node index.js",
+    "test": "jest --forceExit"
+  },
+  "dependencies": {
+    "@ttrpg/shared": "*",
+    "better-sqlite3": "^11.3.0",
+    "cors": "^2.8.5",
+    "express": "^4.19.2",
+    "nanoid": "^5.0.7",
+    "ws": "^8.18.0"
+  },
+  "devDependencies": {
+    "jest": "^29.7.0",
+    "supertest": "^7.0.0"
+  }
+}

server/tests/server-contract.test.js

@@ -0,0 +1,34 @@
+// Layer 2 test: exercise server.js storage adapter against a LIVE backend.
+// Complements Layer 1 (App + firebase mock) which proves App call shape but
+// never touches ws.js. This catches translation bugs in the adapter.
+//
+// Runs the shared storage contract (same spec memory/firebase satisfy) against
+// createServerStorage pointed at an ephemeral backend instance. A FRESH backend is
+// spun up per test to guarantee isolation (backend has no reset endpoint yet).
+
+'use strict';
+
+const path = require('path');
+const os = require('os');
+const { createServer } = require('../index');
+const { createServerStorage } = require('../../src/storage/server');
+const { runStorageContract } = require('../../src/storage/contract');
+
+// Factory: fresh backend (unique sqlite file) + storage pointed at it.
+// Disposing the storage closes the backend so each test is fully isolated.
+async function makeStorage() {
+  const dbPath = path.join(os.tmpdir(), `ws-contract-${Date.now()}-${Math.random().toString(36).slice(2)}.sqlite`);
+  const handle = createServer({ dbPath, port: 0 });
+  await new Promise((resolve, reject) => {
+    handle.server.on('error', reject);
+    handle.server.listen(0, resolve);
+  });
+  const port = handle.server.address().port;
+  const baseUrl = `http://127.0.0.1:${port}`;
+  const wsUrl = `ws://127.0.0.1:${port}/ws`;
+  const storage = createServerStorage({ baseUrl, realtimeUrl: wsUrl });
+  storage.dispose = (done) => handle.close(done);
+  return storage;
+}
+
+runStorageContract('server (live backend)', makeStorage);

server/tests/server-reconnect.test.js

@@ -0,0 +1,56 @@
+// BUG-8: ws adapter has NO reconnect. WS dies (idle/error/close) → wsReady=null,
+// subscribers dead forever, no re-subscribe. Display frozen until full reload.
+// Test: subscribe, write (cb fires), force-drop WS, write again (must still fire).
+// RED on current.
+
+'use strict';
+
+const path = require('path');
+const os = require('os');
+const { createServer } = require('../index');
+const { createServerStorage } = require('../../src/storage/server');
+
+const flush = (ms = 150) => new Promise(r => setTimeout(r, ms));
+
+async function makeStorage() {
+  const dbPath = path.join(os.tmpdir(), `ws-recon-${Date.now()}-${Math.random().toString(36).slice(2)}.sqlite`);
+  const handle = createServer({ dbPath, port: 0 });
+  await new Promise((resolve, reject) => {
+    handle.server.on('error', reject);
+    handle.server.listen(0, resolve);
+  });
+  const port = handle.server.address().port;
+  const baseUrl = `http://127.0.0.1:${port}`;
+  const wsUrl = `ws://127.0.0.1:${port}/ws`;
+  const storage = createServerStorage({ baseUrl, realtimeUrl: wsUrl });
+  storage.dispose = (done) => handle.close(done);
+  return storage;
+}
+
+describe('BUG-8: ws adapter reconnect after drop', () => {
+  test('subscribe fires cb after WS dropped + restored', async () => {
+    const storage = await makeStorage();
+    try {
+      await storage.setDoc('campaigns/a', { name: 'V1' });
+      const calls = [];
+      storage.subscribeDoc('campaigns/a', (doc) => calls.push(doc));
+      await flush();
+      expect(calls.length).toBeGreaterThanOrEqual(1);
+
+      // force-drop WS (simulates idle timeout / network blip)
+      storage._test.forceDrop();
+      await flush(300);
+      // wsReady should be null now
+      expect(storage._test.getReady()).toBeNull();
+
+      // write again — subscriber must re-fire after reconnect
+      await storage.setDoc('campaigns/a', { name: 'V2' });
+      await flush(1000);
+
+      const last = calls[calls.length - 1];
+      expect(last).toEqual({ id: 'a', name: 'V2' });
+    } finally {
+      await new Promise(r => storage.dispose(r));
+    }
+  }, 15000);
+});

shared/index.js

@@ -0,0 +1,2 @@
+// @ttrpg/shared — barrel export.
+module.exports = require('./turn.js');

shared/jest.config.js

@@ -0,0 +1,7 @@
+module.exports = {
+  rootDir: '.',
+  testEnvironment: 'node',
+  testMatch: ['<rootDir>/tests/**/*.test.js'],
+  collectCoverageFrom: ['turn.js'],
+  testTimeout: 10000,
+};

shared/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "@ttrpg/shared",
+  "version": "0.1.0",
+  "private": true,
+  "description": "Pure logic shared by client + server + tests. No I/O.",
+  "main": "index.js",
+  "scripts": {
+    "test": "jest"
+  },
+  "devDependencies": {
+    "jest": "^29.7.0"
+  }
+}

shared/tests/static.no-sort.test.js

@@ -0,0 +1,70 @@
+// STATIC GUARD: no `.sort(` introduced in shared/turn.js outside the ONE
+// allowed function (sortParticipantsByInitiative, used by startEncounter to
+// freeze the list once). Slot-not-sort design (docs/INITIATIVE_ORDERING.md):
+// mutations = insert/move, never wholesale re-sort. A stray `.sort(` after
+// start destroys drag tie-break order.
+//
+// This test errs the moment someone adds `.sort(` anywhere but the allowlist.
+// Maintenance: add a function to ALLOWED only if it runs at startEncounter
+// (one-time freeze), NOT in add/update/reorder/nextTurn paths.
+
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+const SRC = fs.readFileSync(path.join(__dirname, '..', 'turn.js'), 'utf8');
+
+// Functions permitted to call .sort(. Listed so intent is explicit + reviewed.
+const ALLOWED_SORT_FUNCTIONS = new Set([
+  'sortParticipantsByInitiative',
+]);
+
+// Collect top-level function bodies by brace counting.
+// Matches `function NAME(` decls AND `const NAME = ... =>` arrow fns.
+// Returns [{ name, body }].
+function collectBody(src, fromIdx) {
+  let i = fromIdx;
+  while (i < src.length && src[i] !== '{') i++;
+  let depth = 0;
+  const start = i;
+  for (; i < src.length; i++) {
+    if (src[i] === '{') depth++;
+    else if (src[i] === '}') { depth--; if (depth === 0) break; }
+  }
+  return src.slice(start, i + 1);
+}
+
+function extractFunctions(src) {
+  const out = [];
+  const fnRe = /\bfunction\s+([A-Za-z0-9_$]+)\s*\(/g;
+  const arrowRe = /(?:const|let|var)\s+([A-Za-z0-9_$]+)\s*=\s*[^=;]*?=>/g;
+  let m;
+  while ((m = fnRe.exec(src)) !== null) {
+    out.push({ name: m[1], body: collectBody(src, m.index + m[0].length) });
+  }
+  while ((m = arrowRe.exec(src)) !== null) {
+    out.push({ name: m[1], body: collectBody(src, m.index + m[0].length) });
+  }
+  return out;
+}
+
+describe('STATIC: no .sort( outside allowlist (slot-not-sort design)', () => {
+  test('every .sort( call lives in an allowed function', () => {
+    const fns = extractFunctions(SRC);
+    const offenders = [];
+    for (const { name, body } of fns) {
+      if (!ALLOWED_SORT_FUNCTIONS.has(name) && /\.sort\(/.test(body)) {
+        offenders.push(name);
+      }
+    }
+    expect(offenders).toEqual([]);
+  });
+
+  test('allowed sort function is declared (no silent allowlist drift)', () => {
+    const declared = new Set(extractFunctions(SRC).map(f => f.name));
+    for (const name of ALLOWED_SORT_FUNCTIONS) {
+      expect(declared.has(name)).toBe(true);
+    }
+  });
+});

shared/tests/static.no-unlogged.test.js

@@ -0,0 +1,98 @@
+// STATIC GUARD: every mutation logged. Scans shared/turn.js source.
+// Invariant: any return with patch != null MUST also have log != null.
+//   return { patch: {...}, log: {...} }  — OK (logged mutation)
+//   return { patch: null, log: null }    — OK (no-op)
+//   return { patch: {...}, log: null }   — FAIL (unlogged mutation = BUG-7 class)
+//
+// BUG-7 history: reorderParticipants + deathSave + addParticipants +
+// updateParticipant all returned log:null with real patches. Per-op test
+// missed them because gaps section asserted null as "expected." Static scan
+// catches any future regression regardless of test enumeration.
+
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+const SRC = fs.readFileSync(path.join(__dirname, '..', 'turn.js'), 'utf8');
+
+// Extract function name + body via brace counting.
+function collectBody(src, fromIdx) {
+  let i = fromIdx;
+  while (i < src.length && src[i] !== '{') i++;
+  let depth = 0;
+  const start = i;
+  for (; i < src.length; i++) {
+    if (src[i] === '{') depth++;
+    else if (src[i] === '}') { depth--; if (depth === 0) break; }
+  }
+  return src.slice(start, i + 1);
+}
+
+function extractFunctions(src) {
+  const out = [];
+  const fnRe = /\bfunction\s+([A-Za-z0-9_$]+)\s*\(/g;
+  const arrowRe = /(?:const|let|var)\s+([A-Za-z0-9_$]+)\s*=\s*[^=;]*?=>/g;
+  let m;
+  while ((m = fnRe.exec(src)) !== null) {
+    out.push({ name: m[1], body: collectBody(src, m.index + m[0].length) });
+  }
+  while ((m = arrowRe.exec(src)) !== null) {
+    out.push({ name: m[1], body: collectBody(src, m.index + m[0].length) });
+  }
+  return out;
+}
+
+// Split body into return statements at top level of the function.
+// Returns array of return-expr strings.
+function extractReturns(body) {
+  const returns = [];
+  // find `return ` at depth 1 (inside fn body)
+  let i = 0;
+  // body starts with `{`. Skip into depth 1.
+  while (i < body.length && body[i] !== '{') i++;
+  i++; // past {
+  let depth = 1;
+  let start = -1;
+  for (; i < body.length; i++) {
+    const ch = body[i];
+    if (ch === '{') depth++;
+    else if (ch === '}') depth--;
+    if (depth === 1 && body.slice(i, i + 7) === 'return ') {
+      start = i + 7;
+    }
+    if (depth === 1 && ch === ';' && start !== -1) {
+      returns.push(body.slice(start, i));
+      start = -1;
+    }
+  }
+  return returns;
+}
+
+// For a return expr, detect: has `log: null` AND has `patch:` that is NOT null.
+// Returns true if suspicious (unlogged mutation).
+function isUnloggedMutation(retExpr) {
+  if (!/log:\s*null/.test(retExpr)) return false;
+  // patch: null  → no-op, OK
+  if (/patch:\s*null/.test(retExpr)) return false;
+  // patch: { ... } or patch: someVar → mutation with null log = BAD
+  if (/patch:/.test(retExpr)) return true;
+  return false;
+}
+
+describe('STATIC: every mutation logged (logging contract)', () => {
+  const fns = extractFunctions(SRC);
+
+  test('no function returns patch!=null with log:null', () => {
+    const offenders = [];
+    for (const { name, body } of fns) {
+      const rets = extractReturns(body);
+      for (const r of rets) {
+        if (isUnloggedMutation(r)) {
+          offenders.push(`${name}: return ${r.trim().slice(0, 80)}`);
+        }
+      }
+    }
+    expect(offenders).toEqual([]);
+  });
+});

shared/tests/turn.bug10.test.js

@@ -0,0 +1,82 @@
+// BUG-10: deact+reactivate same round double-acts participant.
+// OLD bug: reactivation re-inserted by initiative (front of pointer) →
+// participant acted again before round end.
+//
+// 1-list model: toggleActive keeps slot position. Reactivation does NOT
+// grant second turn. Each participant acts at most once per round.
+//
+// Test: walk rounds, count visits. Deactivate+reactivate mid-round must
+// not cause any participant to act twice in same round.
+
+'use strict';
+
+const shared = require('@ttrpg/shared');
+const {
+  makeParticipant,
+  startEncounter, nextTurn, toggleParticipantActive,
+} = shared;
+
+function p(id, init) {
+  return makeParticipant({ id, name: id, type: 'monster',
+    initiative: init, maxHp: 100, currentHp: 100 });
+}
+function enc(ps) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[] };
+}
+const apply = (e, r) => r && r.patch ? { ...e, ...r.patch } : e;
+
+describe('BUG-10: deact+reactivate same round', () => {
+  test('no participant acts twice in a round after deact+reactivate', () => {
+    // [a(10), b(7), c(3)]
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e)); // a current, r1
+
+    const r1 = [];
+    r1.push(e.currentTurnParticipantId); // a acts
+    e = apply(e, nextTurn(e)); r1.push(e.currentTurnParticipantId); // b acts
+
+    // b already acted. Deactivate b (NOT current now — b just became current
+    // via nextTurn, so b IS current). Toggle off advances pointer to c.
+    e = apply(e, toggleParticipantActive(e, 'b')); // b off
+    // current advanced to c (b was current)
+    r1.push(e.currentTurnParticipantId); // c "becomes" active turn
+    // reactivate b same round
+    e = apply(e, toggleParticipantActive(e, 'b')); // b on
+
+    // nextTurn from c → round 2 (a). b must NOT re-act in round 1.
+    e = apply(e, nextTurn(e));
+    expect(e.round).toBe(2);
+    expect(e.currentTurnParticipantId).toBe('a');
+
+    // b acted once in r1, must act once in r2
+    e = apply(e, nextTurn(e));
+    expect(e.currentTurnParticipantId).toBe('b');
+    e = apply(e, nextTurn(e));
+    expect(e.currentTurnParticipantId).toBe('c');
+
+    // per-round visit count
+    const bCountR1 = r1.filter(id => id === 'b').length;
+    expect(bCountR1).toBe(1);
+  });
+
+  test('deactivate+reactivate non-current who already acted: no re-act', () => {
+    // [a(10), b(7), c(3)]. a acts, b acts, c acts (round 1 done).
+    // Then deactivate a (already acted, not current since c is current).
+    // Reactivate a. a must not act again until round 2.
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e)); // a
+    e = apply(e, nextTurn(e)); // b
+    e = apply(e, nextTurn(e)); // c (r1 full: a,b,c)
+    // c is current. deactivate a (not current, already acted).
+    e = apply(e, toggleParticipantActive(e, 'a')); // a off, pointer stays c
+    expect(e.currentTurnParticipantId).toBe('c');
+    e = apply(e, toggleParticipantActive(e, 'a')); // a on
+    expect(e.currentTurnParticipantId).toBe('c');
+
+    // nextTurn from c → a (round 2). a acts in r2, once.
+    e = apply(e, nextTurn(e));
+    expect(e.round).toBe(2);
+    expect(e.currentTurnParticipantId).toBe('a');
+  });
+});

shared/tests/turn.bug13.test.js

@@ -0,0 +1,72 @@
+// BUG-13: cross-pointer reorder blocked (skip/double-act otherwise).
+// nextTurn walks turnOrderIds forward from current pointer. Dragging across
+// pointer = ambiguous who-acts-next:
+//   - upcoming dragged ahead of pointer → walk wraps past → SKIPPED
+//   - acted dragged behind pointer → acts again → DOUBLE-ACT
+// Full fix needs actedThisRound tracking. Pragmatic now: block both dirs
+// during active encounter. Pre-combat: free reorder (no pointer).
+
+'use strict';
+
+const shared = require('@ttrpg/shared');
+const {
+  makeParticipant,
+  startEncounter, nextTurn, reorderParticipants,
+} = shared;
+
+function p(id, init) {
+  return makeParticipant({ id, name: id, type: 'monster',
+    initiative: init, maxHp: 100, currentHp: 100 });
+}
+function enc(ps) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[] };
+}
+const apply = (e, r) => r && r.patch ? { ...e, ...r.patch } : e;
+
+describe('BUG-13: cross-pointer reorder blocked during active encounter', () => {
+  test('dragging not-yet-acted participant ahead of pointer = no-op', () => {
+    // [a(10), b(10), c(10)]. a acts -> b current. c not yet acted.
+    let e = enc([p('a',10),p('b',10),p('c',10)]);
+    e = apply(e, startEncounter(e)); // a (idx0, pointer)
+    e = apply(e, nextTurn(e)); // b (idx1, pointer)
+    expect(e.currentTurnParticipantId).toBe('b');
+
+    // Drag c (idx2, behind pointer) before b (idx1, pointer). Crosses pointer.
+    // Would let c act by initiative-reinsert but nextTurn forward-walk skips.
+    // Blocked instead.
+    const r = reorderParticipants(e, 'c', 'b');
+    expect(r.patch).toBeNull();
+    expect(e.turnOrderIds).toEqual(['a','b','c']); // unchanged
+  });
+
+  test('dragging already-acted participant behind pointer = no-op', () => {
+    // [a(10), b(10), c(10)]. a acts (idx0, ahead of pointer).
+    let e = enc([p('a',10),p('b',10),p('c',10)]);
+    e = apply(e, startEncounter(e)); // a (pointer idx0)
+    e = apply(e, nextTurn(e)); // b (pointer idx1)
+    // Drag a (already acted, ahead of pointer) after c (behind pointer).
+    // Crosses pointer. Would let a act again. Blocked.
+    const r = reorderParticipants(e, 'a', 'c');
+    expect(r.patch).toBeNull();
+  });
+
+  test('reorder within same side of pointer = allowed', () => {
+    // [a(10), b(10), c(10), d(10)]. a current (pointer idx0).
+    // b,c,d all behind pointer (upcoming). Reorder among them = safe.
+    let e = enc([p('a',10),p('b',10),p('c',10),p('d',10)]);
+    e = apply(e, startEncounter(e)); // a (idx0)
+    // swap b,c (both idx1,2 — behind pointer). No cross.
+    const r = reorderParticipants(e, 'c', 'b');
+    expect(r.patch).not.toBeNull();
+    expect(r.patch.participants.map(p => p.id)).toEqual(['a','c','b','d']);
+  });
+
+  test('pre-combat: free reorder (no pointer)', () => {
+    // isStarted=false. No pointer. Reorder allowed freely.
+    let e = enc([p('a',10),p('b',10),p('c',10)]);
+    const r = reorderParticipants(e, 'c', 'a');
+    expect(r.patch).not.toBeNull();
+    expect(r.patch.participants.map(p => p.id)).toEqual(['c','a','b']);
+  });
+});

shared/tests/turn.bug7.test.js

@@ -0,0 +1,54 @@
+// BUG-7: reorderParticipants not logged.
+// Every combat op returns { patch, log }. Handler calls logAction(log.message,
+// ctx, { updates: log.undo }) → writes entry to logs collection.
+// reorderParticipants returns log: null → handler skips logAction → drag
+// invisible in combat log + no undo payload (siblings all have one).
+//
+// RED: prove log is null (bug). Fix: return { message, undo }.
+
+'use strict';
+
+const shared = require('@ttrpg/shared');
+const { makeParticipant, reorderParticipants } = shared;
+
+function p(id, init) {
+  return makeParticipant({ id, name: id, type: 'monster',
+    initiative: init, maxHp: 100, currentHp: 100 });
+}
+function enc(ps) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[] };
+}
+
+describe('BUG-7: reorderParticipants logged', () => {
+  test('returns log object (not null) with message + undo', () => {
+    const e = enc([p('a', 10), p('b', 10), p('c', 10)]);
+    const r = reorderParticipants(e, 'c', 'b');
+    expect(r.patch).not.toBeNull();
+    expect(r.log).not.toBeNull();
+    expect(typeof r.log.message).toBe('string');
+    expect(r.log.message.length).toBeGreaterThan(0);
+    expect(r.log.undo).toBeDefined();
+  });
+
+  test('undo restores original participants order', () => {
+    const e = enc([p('a', 10), p('b', 10), p('c', 10)]);
+    const orig = e.participants.map(p => p.id);
+    const r = reorderParticipants(e, 'c', 'b');
+    const restored = { ...e, ...r.log.undo };
+    expect(restored.participants.map(p => p.id)).toEqual(orig);
+  });
+
+  test('no-op (same id) returns null log', () => {
+    const e = enc([p('a', 10), p('b', 10)]);
+    const r = reorderParticipants(e, 'a', 'a');
+    expect(r.log).toBeNull();
+  });
+
+  test('no-op (cross-init blocked) returns null log', () => {
+    const e = enc([p('a', 10), p('b', 5)]);
+    const r = reorderParticipants(e, 'a', 'b');
+    expect(r.patch).toBeNull();
+    expect(r.log).toBeNull();
+  });
+});

shared/tests/turn.characterization.test.js

@@ -0,0 +1,344 @@
+// Characterization tests for shared/turn.js.
+// Lock CURRENT behavior (bugs included). M3 will extend, M4 will fix.
+// These tests assert what the code does NOW, not what it SHOULD do.
+
+const shared = require('@ttrpg/shared');
+const {
+  sortParticipantsByInitiative,
+  computeTurnOrderAfterRemoval,
+  startEncounter,
+  nextTurn,
+  togglePause,
+  addParticipant,
+  removeParticipant,
+  toggleParticipantActive,
+  applyHpChange,
+  deathSave,
+  toggleCondition,
+  reorderParticipants,
+  endEncounter,
+  makeParticipant,
+} = shared;
+
+// Helper: minimal encounter with given participants.
+function enc(participants = [], extra = {}) {
+  return {
+    name: 'Test Encounter',
+    participants,
+    isStarted: false,
+    isPaused: false,
+    round: 0,
+    currentTurnParticipantId: null,
+    turnOrderIds: [],
+    ...extra,
+  };
+}
+
+function p(id, initiative, extra = {}) {
+  return makeParticipant({
+    id, name: id, type: 'monster',
+    initiative, maxHp: 20, currentHp: 20,
+    ...extra,
+  });
+}
+
+describe('sortParticipantsByInitiative', () => {
+  test('higher initiative first', () => {
+    const ps = [p('a', 5), p('b', 15), p('c', 10)];
+    const sorted = sortParticipantsByInitiative(ps, ps);
+    expect(sorted.map(x => x.id)).toEqual(['b', 'c', 'a']);
+  });
+
+  test('ties broken by original order', () => {
+    const ps = [p('a', 10), p('b', 10), p('c', 10)];
+    const sorted = sortParticipantsByInitiative(ps, ps);
+    expect(sorted.map(x => x.id)).toEqual(['a', 'b', 'c']);
+  });
+});
+
+describe('startEncounter', () => {
+  test('throws if no participants', () => {
+    expect(() => startEncounter(enc([]))).toThrow('participants');
+  });
+
+  test('throws if no active participants', () => {
+    const e = enc([p('a', 10, { isActive: false })]);
+    expect(() => startEncounter(e)).toThrow('active');
+  });
+
+  test('sets round 1, turn order sorted, current = highest init', () => {
+    const ps = [p('a', 5), p('b', 15), p('c', 10)];
+    const e = enc(ps);
+    const { patch } = startEncounter(e);
+    expect(patch.isStarted).toBe(true);
+    expect(patch.round).toBe(1);
+    expect(patch.turnOrderIds).toEqual(['b', 'c', 'a']);
+    expect(patch.currentTurnParticipantId).toBe('b');
+  });
+
+  test('inactive stays in turn order slot (1-list model)', () => {
+    const ps = [p('a', 5), p('b', 15, { isActive: false }), p('c', 10)];
+    const { patch } = startEncounter(enc(ps));
+    // 1-list: all participants sorted by init (active+inactive), inactive stays in slot
+    expect(patch.turnOrderIds).toEqual(['b', 'c', 'a']);
+    expect(patch.currentTurnParticipantId).toBe('c'); // b inactive, skipped
+  });
+});
+
+describe('nextTurn', () => {
+  test('throws if not started', () => {
+    expect(() => nextTurn(enc([p('a', 10)], { isStarted: false }))).toThrow();
+  });
+
+  test('throws if paused', () => {
+    expect(() => nextTurn(enc([p('a', 10)], { isStarted: true, isPaused: true, currentTurnParticipantId: 'a', turnOrderIds: ['a'] }))).toThrow();
+  });
+
+  test('advances to next in order, no round bump', () => {
+    const ps = [p('a', 5), p('b', 15), p('c', 10)];
+    const e = enc(ps, {
+      isStarted: true,
+      round: 1,
+      currentTurnParticipantId: 'b',
+      turnOrderIds: ['b', 'c', 'a'],
+    });
+    const { patch } = nextTurn(e);
+    expect(patch.currentTurnParticipantId).toBe('c');
+    expect(patch.round).toBe(1);
+  });
+
+  test('wraps round when last in order', () => {
+    const ps = [p('a', 5), p('b', 15), p('c', 10)];
+    const e = enc(ps, {
+      isStarted: true,
+      round: 1,
+      currentTurnParticipantId: 'a',
+      turnOrderIds: ['b', 'c', 'a'],
+    });
+    const { patch } = nextTurn(e);
+    expect(patch.currentTurnParticipantId).toBe('b');
+    expect(patch.round).toBe(2);
+  });
+
+  test('ends encounter if no active participants', () => {
+    const ps = [p('a', 10, { isActive: false })];
+    const e = enc(ps, {
+      isStarted: true,
+      round: 1,
+      currentTurnParticipantId: 'a',
+      turnOrderIds: ['a'],
+    });
+    const { patch } = nextTurn(e);
+    expect(patch.isStarted).toBe(false);
+    expect(patch.currentTurnParticipantId).toBe(null);
+  });
+});
+
+describe('togglePause', () => {
+  test('pauses started encounter', () => {
+    const e = enc([p('a', 10)], { isStarted: true, isPaused: false });
+    const { patch } = togglePause(e);
+    expect(patch.isPaused).toBe(true);
+  });
+
+  test('resume preserves turn order (no re-sort)', () => {
+    // BUG-5 fix: resume no longer re-sorts. Re-sort displaced current pointer
+    // and caused skips. Order frozen at startEncounter, patched incrementally.
+    const ps = [p('a', 5), p('b', 15)];
+    const e = enc(ps, { isStarted: true, isPaused: true, turnOrderIds: ['a', 'b'] });
+    const { patch } = togglePause(e);
+    expect(patch.isPaused).toBe(false);
+    expect(patch.turnOrderIds).toEqual(['a', 'b']);
+  });
+});
+
+describe('removeParticipant', () => {
+  test('removes from participants array', () => {
+    const ps = [p('a', 10), p('b', 5)];
+    const { patch } = removeParticipant(enc(ps), 'a');
+    expect(patch.participants.map(x => x.id)).toEqual(['b']);
+  });
+
+  test('not started: no turn order mutation', () => {
+    const ps = [p('a', 10), p('b', 5)];
+    const { patch } = removeParticipant(enc(ps), 'a');
+    expect(patch.turnOrderIds).toBeUndefined();
+  });
+
+  test('started: removes from turnOrderIds', () => {
+    const ps = [p('a', 10), p('b', 5)];
+    const e = enc(ps, { isStarted: true, turnOrderIds: ['a', 'b'], currentTurnParticipantId: 'b' });
+    const { patch } = removeParticipant(e, 'a');
+    expect(patch.turnOrderIds).toEqual(['b']);
+  });
+
+  test('started: removing current picks next active', () => {
+    const ps = [p('a', 10), p('b', 5), p('c', 3)];
+    const e = enc(ps, { isStarted: true, turnOrderIds: ['a', 'b', 'c'], currentTurnParticipantId: 'a' });
+    const { patch } = removeParticipant(e, 'a');
+    expect(patch.currentTurnParticipantId).toBe('b');
+  });
+});
+
+describe('toggleParticipantActive', () => {
+  test('deactivates participant', () => {
+    const ps = [p('a', 10, { isActive: true })];
+    const { patch } = toggleParticipantActive(enc(ps), 'a');
+    expect(patch.participants[0].isActive).toBe(false);
+  });
+
+  test('started: deactivating current advances turn', () => {
+    const ps = [p('a', 10), p('b', 5)];
+    const e = enc(ps, { isStarted: true, turnOrderIds: ['a', 'b'], currentTurnParticipantId: 'a' });
+    const { patch } = toggleParticipantActive(e, 'a');
+    expect(patch.currentTurnParticipantId).toBe('b');
+  });
+
+  test('started: reactivating inserts by initiative', () => {
+    // BUG-5 fix: reactivated participant slots by initiative (not appended
+    // to end). Preserves correct rotation order.
+    const ps = [p('a', 10, { isActive: false }), p('b', 5)];
+    const e = enc(ps, { isStarted: true, turnOrderIds: ['b'], currentTurnParticipantId: 'b' });
+    const { patch } = toggleParticipantActive(e, 'a');
+    // a init=10 > b init=5 → a slots before b
+    expect(patch.turnOrderIds).toEqual(['a', 'b']);
+  });
+});
+
+describe('applyHpChange', () => {
+  test('damage reduces hp, clamps 0', () => {
+    const ps = [p('a', 10, { currentHp: 15, maxHp: 20 })];
+    const { patch } = applyHpChange(enc(ps), 'a', 'damage', 5);
+    expect(patch.participants[0].currentHp).toBe(10);
+  });
+
+  test('damage to 0 deactivates + keeps turn order (unified)', () => {
+    // Unified: death flips isActive=false (removed from active rotation).
+    // turnOrderIds unchanged (no turn-order patch on death).
+    const ps = [p('a', 10, { currentHp: 3 }), p('b', 5)];
+    const e = enc(ps, { isStarted: true, turnOrderIds: ['a', 'b'], currentTurnParticipantId: 'a' });
+    const { patch } = applyHpChange(e, 'a', 'damage', 5);
+    expect(patch.participants[0].currentHp).toBe(0);
+    expect(patch.participants[0].isActive).toBe(false);
+    expect(patch.turnOrderIds).toBeUndefined();
+    expect(patch.currentTurnParticipantId).toBeUndefined();
+  });
+
+  test('heal above 0 reactivates + resets death saves (unified)', () => {
+    // Unified: revive from 0 flips isActive=true, deathSaves reset.
+    const ps = [p('a', 10, { currentHp: 0, isActive: false, deathSaves: 2 })];
+    const { patch } = applyHpChange(enc(ps), 'a', 'heal', 5);
+    expect(patch.participants[0].currentHp).toBe(5);
+    expect(patch.participants[0].isActive).toBe(true);
+    expect(patch.participants[0].deathSaves).toBe(0);
+  });
+
+  test('heal clamps to maxHp', () => {
+    const ps = [p('a', 10, { currentHp: 18, maxHp: 20 })];
+    const { patch } = applyHpChange(enc(ps), 'a', 'heal', 10);
+    expect(patch.participants[0].currentHp).toBe(20);
+  });
+
+  test('zero amount = no-op', () => {
+    const ps = [p('a', 10, { currentHp: 10 })];
+    const { patch } = applyHpChange(enc(ps), 'a', 'damage', 0);
+    expect(patch).toBe(null);
+  });
+});
+
+describe('deathSave', () => {
+  test('increments fails', () => {
+    const ps = [p('a', 10, { currentHp: 0, deathFails: 0 })];
+    const { patch } = deathSave(enc(ps), 'a', 'fail', 1);
+    expect(patch.participants[0].deathFails).toBe(1);
+  });
+
+  test('clicking same fail decrements (toggle)', () => {
+    const ps = [p('a', 10, { currentHp: 0, deathFails: 2 })];
+    const { patch } = deathSave(enc(ps), 'a', 'fail', 2);
+    expect(patch.participants[0].deathFails).toBe(1);
+  });
+
+  test('third fail sets isDying', () => {
+    const ps = [p('a', 10, { currentHp: 0, deathFails: 2 })];
+    const result = deathSave(enc(ps), 'a', 'fail', 3);
+    expect(result.patch.participants[0].deathFails).toBe(3);
+    expect(result.patch.participants[0].isDying).toBe(true);
+    expect(result.isDying).toBe(true);
+  });
+});
+
+describe('toggleCondition', () => {
+  test('adds condition', () => {
+    const ps = [p('a', 10, { conditions: [] })];
+    const { patch } = toggleCondition(enc(ps), 'a', 'poisoned');
+    expect(patch.participants[0].conditions).toEqual(['poisoned']);
+  });
+
+  test('removes condition', () => {
+    const ps = [p('a', 10, { conditions: ['poisoned', 'blinded'] })];
+    const { patch } = toggleCondition(enc(ps), 'a', 'poisoned');
+    expect(patch.participants[0].conditions).toEqual(['blinded']);
+  });
+});
+
+describe('reorderParticipants', () => {
+  test('drag before target (same-init tie)', () => {
+    const ps = [p('a', 10), p('b', 10), p('c', 10)];
+    const { patch } = reorderParticipants(enc(ps), 'a', 'c');
+    // drag a before c: remove a → [b,c], insert before c → [b,a,c]
+    expect(patch.participants.map(x => x.id)).toEqual(['b', 'a', 'c']);
+  });
+
+  test('cross-init drag blocked (no-op)', () => {
+    const ps = [p('a', 10), p('b', 5)];
+    const { patch } = reorderParticipants(enc(ps), 'a', 'b');
+    expect(patch).toBeNull();
+  });
+});
+
+describe('endEncounter', () => {
+  test('resets all combat state', () => {
+    const e = enc([p('a', 10)], {
+      isStarted: true, round: 5, currentTurnParticipantId: 'a', turnOrderIds: ['a'],
+    });
+    const { patch } = endEncounter(e);
+    expect(patch.isStarted).toBe(false);
+    expect(patch.round).toBe(0);
+    expect(patch.currentTurnParticipantId).toBe(null);
+    expect(patch.turnOrderIds).toEqual([]);
+  });
+});
+
+describe('computeTurnOrderAfterRemoval', () => {
+  test('not started = empty', () => {
+    const out = computeTurnOrderAfterRemoval(enc([]), 'a', []);
+    expect(out).toEqual({});
+  });
+
+  test('removing non-current: no turnOrderIds patch (1-list syncs at call site)', () => {
+    const e = enc([], { isStarted: true, turnOrderIds: ['a', 'b'], currentTurnParticipantId: 'b' });
+    const out = computeTurnOrderAfterRemoval(e, 'a', []);
+    // 1-list: removal syncs turnOrderIds via participants[] at call site.
+    // Helper only handles current-advance. Non-current = empty patch.
+    expect(out).toEqual({});
+  });
+});
+
+describe('addParticipant', () => {
+  test('appends participant', () => {
+    const np = p('z', 7);
+    const { patch } = addParticipant(enc([p('a', 10)]), np);
+    expect(patch.participants.map(x => x.id)).toEqual(['a', 'z']);
+  });
+
+  test('rejects duplicate id (skip-bug root cause)', () => {
+    // Two participants with same id → togglePause resume rebuilds order with
+    // dup id twice → nextTurn gets stuck repeating that id forever.
+    // Audit found this in 100-round replay (addParticipant fired while paused
+    // because nextTurn threw, loop spun, same totalTurns %10 → re-added).
+    const existing = p('x', 5);
+    const dup = makeParticipant({ id: 'x', name: 'x2', type: 'monster', initiative: 10, maxHp: 100, currentHp: 100 });
+    expect(() => addParticipant(enc([p('a', 10), existing]), dup)).toThrow();
+  });
+});

shared/tests/turn.combat.test.js

@@ -0,0 +1,294 @@
+// Combat integrity test: replay exact op sequence through pure turn.js,
+// assert rotation + state invariants per round. This IS the test the audit
+// was supposed to be. Deterministic (seeded RNG). RED on current code = BUG-5.
+//
+// Mirrors scripts/replay-combat.js op order:
+//   damage, heal (cleric), conditions, toggleActive, deathSave,
+//   removeParticipant, addParticipant, updateParticipant, pause/resume,
+//   reorderParticipants, revive-between-rounds.
+
+const shared = require('@ttrpg/shared');
+const {
+  makeParticipant, buildCharacterParticipant, buildMonsterParticipant,
+  startEncounter, nextTurn, togglePause,
+  addParticipant, updateParticipant, removeParticipant,
+  toggleParticipantActive, applyHpChange, deathSave,
+  toggleCondition, reorderParticipants, endEncounter,
+} = shared;
+
+// ---- seeded RNG (deterministic, reproducible) ----
+let _seed = 12345;
+function rand() {
+  // LCG
+  _seed = (_seed * 1103515245 + 12345) & 0x7fffffff;
+  return _seed / 0x7fffffff;
+}
+const rnd = (n) => Math.floor(rand() * n);
+const pick = (arr) => arr[rnd(arr.length)];
+
+const CONDITIONS = [
+  'alchemist_fire','bardic_inspiration','blinded','charmed','deafened',
+  'exhaustion','frightened','grappled','grazed','incapacitated',
+  'invisible','paralyzed','petrified','poisoned','prone','restrained',
+  'sapped','shield','slowed','stunned','unconscious','vexed',
+];
+// Custom (non-built-in) condition ids: DM-added freeform strings.
+// toggleCondition must accept ANY string (UI custom-condition contract).
+const CUSTOM_CONDITIONS = ['hexed', 'rager', 'marked_for_death', '🛡️blessed'];
+
+function p(id, init, extra = {}) {
+  return makeParticipant({
+    id, name: id, type: 'monster',
+    initiative: init, maxHp: 200, currentHp: 200,
+    ...extra,
+  });
+}
+
+function setupEncounter() {
+  const ps = [
+    buildCharacterParticipant({ id:'c1', name:'Fighter', defaultMaxHp:200, defaultInitMod:2 }).participant,
+    buildCharacterParticipant({ id:'c2', name:'Cleric', defaultMaxHp:180, defaultInitMod:1 }).participant,
+    buildCharacterParticipant({ id:'c3', name:'Rogue', defaultMaxHp:160, defaultInitMod:3 }).participant,
+    buildMonsterParticipant({ name:'Goblin1', maxHp:100, initMod:2 }).participant,
+    buildMonsterParticipant({ name:'Goblin2', maxHp:100, initMod:2 }).participant,
+    buildMonsterParticipant({ name:'OrcBoss', maxHp:500, initMod:1 }).participant,
+    buildMonsterParticipant({ name:'Wolf', maxHp:120, initMod:3 }).participant,
+    buildMonsterParticipant({ name:'Merchant', maxHp:150, initMod:0, isNpc:true }).participant,
+  ];
+  // give deterministic ids to monsters for assertions
+  const idMap = { Goblin1:'m1', Goblin2:'m2', OrcBoss:'m3', Wolf:'m4', Merchant:'n1' };
+  ps.forEach((part) => { if (idMap[part.name]) part.id = idMap[part.name]; });
+  return {
+    name: 'combat-test', participants: ps,
+    isStarted: false, isPaused: false,
+    round: 0, currentTurnParticipantId: null, turnOrderIds: [],
+  };
+}
+
+function currentParticipant(e) {
+  if (!e.currentTurnParticipantId) return null;
+  return (e.participants || []).find(x => x.id === e.currentTurnParticipantId) || null;
+}
+
+// Apply a result patch if present.
+function apply(e, result) {
+  if (!result || !result.patch) return e;
+  return { ...e, ...result.patch };
+}
+
+describe('combat integrity (100 rounds, full op coverage)', () => {
+  jest.setTimeout(30000);
+
+  const ROUNDS = 100;
+  const violations = [];
+
+  test('every round visits each active participant exactly once', () => {
+    _seed = 12345; // reset for reproducibility
+    let e = setupEncounter();
+    e = apply(e, startEncounter(e));
+
+    let totalTurns = 0;
+    let lastPaused = false;
+    let lastReorder = 0;
+    let reinforcementsAdded = 0;
+    // built-ins first, then custom (proves arbitrary string accepted)
+    const condQueue = [...CONDITIONS, ...CUSTOM_CONDITIONS];
+
+    for (let roundN = 1; roundN <= ROUNDS; roundN++) {
+      const startRound = e.round;
+      const seenThisRound = [];
+      const cap = (e.participants.length + 2) * 2;
+      let guard = 0;
+
+      while (e.round === startRound && guard < cap) {
+        // resume if paused (must precede nextTurn)
+        if (lastPaused) { e = apply(e, togglePause(e)); lastPaused = false; }
+
+        // advance
+        let t;
+        try { t = nextTurn(e); } catch (err) {
+          violations.push({ round: roundN, type: 'nextTurn-throws', msg: err.message });
+          break;
+        }
+        e = apply(e, t);
+        totalTurns++;
+        // only count if turn belongs to THIS round (no wrap)
+        if (e.round === startRound) seenThisRound.push(e.currentTurnParticipantId);
+
+        const actor = currentParticipant(e);
+
+        // 1. damage
+        if (actor) {
+          const foes = e.participants.filter(
+            p => p.id !== actor.id && p.currentHp > 0 && p.isActive !== false
+          );
+          if (foes.length > 0) {
+            const tgt = pick(foes);
+            const dmg = 1 + rnd(5);
+            e = apply(e, applyHpChange(e, tgt.id, 'damage', dmg));
+          }
+        }
+        // 2. heal (cleric)
+        if (actor && actor.name === 'Cleric' && totalTurns % 2 === 0) {
+          const wounded = e.participants
+            .filter(p => p.currentHp > 0 && p.currentHp < p.maxHp && p.isActive !== false)
+            .sort((a,b)=>(a.currentHp/a.maxHp)-(b.currentHp/b.maxHp));
+          if (wounded.length > 0) {
+            const tgt = wounded[0];
+            const amt = 2 + rnd(5);
+            e = apply(e, applyHpChange(e, tgt.id, 'heal', amt));
+          }
+        }
+        // 3. conditions
+        if (condQueue.length > 0) {
+          const cond = condQueue[0];
+          const living = e.participants.filter(p => p.currentHp > 0 && p.isActive !== false);
+          if (living.length > 0) {
+            const tgt = pick(living);
+            try { e = apply(e, toggleCondition(e, tgt.id, cond)); condQueue.shift(); }
+            catch (err) { condQueue.shift(); }
+          }
+        } else if (totalTurns % 6 === 0) {
+          const living = e.participants.filter(p => p.currentHp > 0 && p.isActive !== false);
+          if (living.length > 0) {
+            const tgt = pick(living);
+            const cond = pick([...CONDITIONS, ...CUSTOM_CONDITIONS]);
+            try { e = apply(e, toggleCondition(e, tgt.id, cond)); } catch (err) {}
+          }
+        }
+        // 4. toggleParticipantActive
+        if (totalTurns % 9 === 0) {
+          const living = e.participants.filter(p => p.currentHp > 0);
+          if (living.length > 0) {
+            const tgt = pick(living);
+            try { e = apply(e, toggleParticipantActive(e, tgt.id)); } catch (err) {}
+          }
+        }
+        // 5. deathSave
+        if (actor && actor.currentHp <= 0 && !actor.isNpc) {
+          try { e = apply(e, deathSave(e, actor.id, 'fail', 1)); } catch (err) {}
+        }
+        // 6. removeParticipant
+        if (totalTurns % 5 === 0) {
+          const dead = e.participants.find(p => (p.isDying || p.currentHp <= 0) && (p.isNpc || p.name.startsWith('Goblin') || p.name === 'OrcBoss' || p.name === 'Wolf'));
+          if (dead) { try { e = apply(e, removeParticipant(e, dead.id)); } catch (err) {} }
+        }
+        // 7. addParticipant
+        if (totalTurns % 10 === 0 && reinforcementsAdded < 4) {
+          const spec = pick([
+            { name:`Reinforce${reinforcementsAdded+1}`, maxHp:120, initMod:1 },
+            { name:`Summon${reinforcementsAdded+1}`, maxHp:80, initMod:4 },
+          ]);
+          const built = buildMonsterParticipant(spec).participant;
+          try { e = apply(e, addParticipant(e, built)); reinforcementsAdded++; } catch (err) {}
+        }
+        // 8. updateParticipant
+        if (totalTurns % 7 === 0) {
+          const living = e.participants.filter(p => p.currentHp > 0);
+          if (living.length > 0) {
+            const tgt = pick(living);
+            try { e = apply(e, updateParticipant(e, tgt.id, { notes:`edited@turn${totalTurns}` })); } catch (err) {}
+          }
+        }
+        // 9. pause
+        if (totalTurns % 12 === 0 && !lastPaused) { e = apply(e, togglePause(e)); lastPaused = true; }
+        // 10. reorderParticipants (mirror replay's buggy signature usage — swallowed no-op)
+        if (totalTurns % 8 === 0 && lastReorder !== totalTurns) {
+          const living = e.participants.filter(p => p.currentHp > 0 && p.isActive !== false);
+          if (living.length >= 2) {
+            const tgt = living[0];
+            const newInit = (tgt.initiative || 0) + 1;
+            try {
+              const reordered = [...e.participants].map(p => p.id === tgt.id ? { ...p, initiative: newInit } : p);
+              e = apply(e, reorderParticipants(e, reordered));
+              lastReorder = totalTurns;
+            } catch (err) {}
+          }
+        }
+
+        guard++;
+        if (!e.isStarted) break;
+      }
+      if (!e.isStarted) break;
+
+      // === per-round invariants ===
+      const uniq = new Set(seenThisRound);
+      if (uniq.size !== seenThisRound.length) {
+        violations.push({ round: roundN, type: 'rotation-dupe',
+          seen: seenThisRound.map(id => e.participants.find(p=>p.id===id)?.name||id) });
+      }
+      // turnOrderIds no dup
+      const orderUniq = new Set(e.turnOrderIds);
+      if (orderUniq.size !== e.turnOrderIds.length) {
+        violations.push({ round: roundN, type: 'turnOrder-dup-id', order: e.turnOrderIds });
+      }
+      // currentTurn valid + active
+      if (e.currentTurnParticipantId) {
+        const ct = e.participants.find(p => p.id === e.currentTurnParticipantId);
+        if (!ct) violations.push({ round: roundN, type: 'currentTurn-missing' });
+        else if (ct.isActive === false && e.isStarted) {
+          violations.push({ round: roundN, type: 'currentTurn-inactive', id: ct.id });
+        }
+      }
+      // HP bounds
+      for (const part of e.participants) {
+        if (typeof part.currentHp !== 'number' || isNaN(part.currentHp) || part.currentHp < 0 || part.currentHp > part.maxHp) {
+          violations.push({ round: roundN, type: 'hp-invalid', id: part.id, hp: part.currentHp, max: part.maxHp });
+        }
+        // custom conditions persisted as raw strings (not dropped)
+        for (const c of (part.conditions || [])) {
+          if (typeof c !== 'string' || !c) {
+            violations.push({ round: roundN, type: 'condition-not-string', id: part.id, c });
+          }
+        }
+      }
+      // custom (freeform) conditions must survive toggle round-trip
+      // (presence verified via condition-not-string invariant above;
+      // queue drains them through toggleCondition which proves acceptance)
+
+      // revive dead between rounds
+      const dead = e.participants.filter(p => p.currentHp <= 0 || p.isActive === false);
+      for (const d of dead) {
+        try {
+          if (d.isActive === false) e = apply(e, toggleParticipantActive(e, d.id));
+          e = apply(e, applyHpChange(e, d.id, 'heal', d.maxHp));
+        } catch (err) {}
+      }
+    }
+
+    // Report
+    if (violations.length > 0) {
+      const byType = {};
+      violations.forEach(v => { byType[v.type] = (byType[v.type]||0) + 1; });
+      const summary = Object.entries(byType).sort((a,b)=>b[1]-a[1]).map(([k,n])=>`${n}x ${k}`).join(', ');
+      const first5 = violations.slice(0,5).map(v => `r${v.round} ${v.type}${v.seen?': '+JSON.stringify(v.seen):''}${v.order?': '+JSON.stringify(v.order):''}${v.msg?': '+v.msg:''}`).join('\n  ');
+      // dump full state for first dupe for triage
+      throw new Error(`combat integrity violations: ${violations.length}\n  ${summary}\n  first 5:\n  ${first5}`);
+    }
+    expect(violations).toHaveLength(0);
+  });
+
+  // Custom (freeform) condition strings: UI contract.
+  // toggleCondition must accept ANY string, not just built-ins.
+  test('custom condition strings survive add/remove round-trip', () => {
+    let e = setupEncounter();
+    e = apply(e, startEncounter(e));
+    const tgt = e.participants[0].id;
+
+    // add custom (not in built-ins)
+    e = apply(e, toggleCondition(e, tgt, 'hexed'));
+    let p = e.participants.find(x => x.id === tgt);
+    expect(p.conditions).toContain('hexed');
+
+    // emoji-bearing custom id
+    e = apply(e, toggleCondition(e, tgt, '🛡️blessed'));
+    p = e.participants.find(x => x.id === tgt);
+    expect(p.conditions).toContain('🛡️blessed');
+
+    // remove
+    e = apply(e, toggleCondition(e, tgt, 'hexed'));
+    p = e.participants.find(x => x.id === tgt);
+    expect(p.conditions).not.toContain('hexed');
+    expect(p.conditions).toContain('🛡️blessed');
+  });
+});

shared/tests/turn.dead-skip.test.js

@@ -0,0 +1,90 @@
+// Unified behavior (App main): death flips isActive=false, dead participant
+// removed from active rotation, skipped by nextTurn. deathSave is a manual
+// DM action (button), not tied to rotation. turnOrderIds unchanged on death
+// (only isActive flag flips). Revive (heal from 0) reactivates.
+//
+// Previous "M4: dead stays in rotation" concept reversed by unification.
+
+const shared = require('@ttrpg/shared');
+const { makeParticipant, startEncounter, nextTurn, applyHpChange, deathSave } = shared;
+
+function p(id, init, extra = {}) {
+  return makeParticipant({
+    id, name: id, type: 'monster',
+    initiative: init, maxHp: 100, currentHp: 100,
+    ...extra,
+  });
+}
+function pc(id, init, extra = {}) {
+  return makeParticipant({
+    id, name: id, type: 'character',
+    initiative: init, maxHp: 100, currentHp: 100,
+    ...extra,
+  });
+}
+function enc(ps) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[] };
+}
+
+describe('unified: death deactivates, dead skipped in rotation', () => {
+  test('dead PC not removed from turnOrderIds (stays in list, inactive)', () => {
+    const ps = [pc('a', 20), pc('b', 15), pc('c', 10)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    const orderBefore = e.turnOrderIds.slice();
+    // kill b
+    e = { ...e, ...applyHpChange(e, 'b', 'damage', 100).patch };
+    expect(e.turnOrderIds).toEqual(orderBefore);
+  });
+
+  test('dead PC skipped by nextTurn (isActive=false)', () => {
+    const ps = [pc('a', 20), pc('b', 15), pc('c', 10)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    // kill b
+    e = { ...e, ...applyHpChange(e, 'b', 'damage', 100).patch };
+    // advance: a→c (b skipped, inactive)
+    e = { ...e, ...nextTurn(e).patch };
+    expect(e.currentTurnParticipantId).toBe('c');
+  });
+
+  test('dead PC deathSave fires on manual call (not via rotation)', () => {
+    const ps = [pc('a', 20), pc('b', 15)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    // kill b (current = a)
+    e = { ...e, ...applyHpChange(e, 'b', 'damage', 100).patch };
+    // b is dead: DM can still fire deathSave (manual action)
+    const r = deathSave(e, 'b', 'fail', 1);
+    expect(r.patch).toBeTruthy();
+    const b = r.patch.participants.find(x => x.id === 'b');
+    expect(b.deathFails).toBe(1);
+  });
+
+  // D1 unification: shared now matches App main — death flips isActive=false.
+  // Dead participant removed from active rotation (skipped by nextTurn).
+  test('dead PC auto-set isActive=false by applyHpChange', () => {
+    const ps = [pc('a', 20), pc('b', 15)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    e = { ...e, ...applyHpChange(e, 'b', 'damage', 100).patch };
+    const b = e.participants.find(x => x.id === 'b');
+    expect(b.isActive).toBe(false);
+  });
+
+  test('revive (heal from 0) reactivates participant', () => {
+    const ps = [pc('a', 20), pc('b', 15)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    e = { ...e, ...applyHpChange(e, 'b', 'damage', 100).patch };
+    const dead = e.participants.find(x => x.id === 'b');
+    expect(dead.isActive).toBe(false);
+    // heal b back up
+    e = { ...e, ...applyHpChange(e, 'b', 'heal', 50).patch };
+    const revived = e.participants.find(x => x.id === 'b');
+    expect(revived.isActive).toBe(true);
+    expect(revived.currentHp).toBe(50);
+    expect(revived.deathSaves).toBe(0);
+  });
+});

shared/tests/turn.deathsave.test.js

@@ -0,0 +1,90 @@
+// Death saves: broken model. Current = single counter, 3=dying. D&D 5e needs
+// separate success/fail tracking:
+//   3 successes = stable (0hp unconscious, safe until healed)
+//   3 failures  = dead
+// Current tracks "saves" (really fails via red X UI), no successes at all.
+// "Stable" state doesn't exist.
+//
+// RED: prove current can't model 3-success stability.
+
+'use strict';
+
+const shared = require('@ttrpg/shared');
+const { makeParticipant, startEncounter, applyHpChange, deathSave } = shared;
+
+function p(id) {
+  return makeParticipant({ id, name: id, type: 'character',
+    initiative: 10, maxHp: 100, currentHp: 100 });
+}
+function enc(ps, extra = {}) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[], ...extra };
+}
+const apply = (e, r) => r && r.patch ? { ...e, ...r.patch } : e;
+
+describe('death saves: missing success/stable model', () => {
+  test('3 successes makes character stable (not dead, not dying)', () => {
+    // Character at 0hp. Roll 3 successful death saves.
+    let e = enc([p('a')]);
+    e = apply(e, startEncounter(e));
+    e = apply(e, applyHpChange(e, 'a', 'damage', 100)); // 0hp
+    expect(e.participants[0].currentHp).toBe(0);
+
+    // Roll 3 successful saves. Should mark stable.
+    e = apply(e, deathSave(e, 'a', 'success', 1));
+    e = apply(e, deathSave(e, 'a', 'success', 2));
+    const r3 = deathSave(e, 'a', 'success', 3);
+    e = apply(e, r3);
+
+    // RED: current deathSave signature = (enc, id, saveNumber). No type arg.
+    // Will throw or misbehave. Want: status field.
+    expect(r3.status).toBe('stable');
+    expect(e.participants[0].isDying).toBe(false);
+    expect(e.participants[0].isStable).toBe(true);
+    expect(e.participants[0].deathFails).toBe(0);
+  });
+
+  test('3 failures makes character dead (isDying for removal)', () => {
+    let e = enc([p('a')]);
+    e = apply(e, startEncounter(e));
+    e = apply(e, applyHpChange(e, 'a', 'damage', 100));
+
+    const r1 = deathSave(e, 'a', 'fail', 1);
+    e = apply(e, r1);
+    const r2 = deathSave(e, 'a', 'fail', 2);
+    e = apply(e, r2);
+    const r3 = deathSave(e, 'a', 'fail', 3);
+    e = apply(e, r3);
+
+    expect(r3.status).toBe('dead');
+    expect(e.participants[0].isDying).toBe(true);
+    expect(e.participants[0].deathFails).toBe(3);
+  });
+
+  test('successes and fails tracked independently', () => {
+    // Mixed: 1 success, 2 fails, then 2 more successes = stable.
+    let e = enc([p('a')]);
+    e = apply(e, startEncounter(e));
+    e = apply(e, applyHpChange(e, 'a', 'damage', 100));
+
+    e = apply(e, deathSave(e, 'a', 'success', 1));
+    expect(e.participants[0].deathSaves).toBe(1);
+    expect(e.participants[0].deathFails).toBe(0);
+
+    e = apply(e, deathSave(e, 'a', 'fail', 1));
+    e = apply(e, deathSave(e, 'a', 'fail', 2));
+    expect(e.participants[0].deathSaves).toBe(1);
+    expect(e.participants[0].deathFails).toBe(2);
+
+    // 2 more successes → total 3 successes → stable
+    e = apply(e, deathSave(e, 'a', 'success', 2));
+    const r = deathSave(e, 'a', 'success', 3);
+    expect(r.status).toBe('stable');
+    expect(e.participants[0].deathFails).toBe(2); // fails unchanged
+  });
+
+  test('deathSave signature: (enc, id, type, n)', () => {
+    // type = 'success' | 'fail'. n = 1|2|3.
+    expect(deathSave.length).toBe(4);
+  });
+});

shared/tests/turn.dry.test.js

@@ -0,0 +1,52 @@
+// DRY guard (BUG-5 fix): nextTurn and computeTurnOrderAfterRemoval share one
+// advance core (nextActiveAfter). Both must pick the SAME next-active target
+// for identical state. If this goes RED, the two paths drifted.
+
+'use strict';
+
+const shared = require('@ttrpg/shared');
+const { makeParticipant, startEncounter, nextTurn, toggleParticipantActive } = shared;
+
+function p(id, init, extra = {}) {
+  return makeParticipant({ id, name: id, type: 'monster',
+    initiative: init, maxHp: 100, currentHp: 100, ...extra });
+}
+function enc(ps, extra = {}) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[], ...extra };
+}
+
+describe('DRY: deact-current advance == nextTurn advance', () => {
+  test('mid-round: same target (not current)', () => {
+    // order a,b,c. a current. nextTurn → b. deact a → advance → b.
+    const e = enc([p('a',10),p('b',5),p('c',3)], { isStarted:true,
+      turnOrderIds:['a','b','c'], currentTurnParticipantId:'a' });
+    const nt = nextTurn(e).patch.currentTurnParticipantId;
+    const deact = toggleParticipantActive(e, 'a').patch.currentTurnParticipantId;
+    expect(deact).toBe(nt);
+    expect(deact).toBe('b');
+  });
+
+  test('mid-round with inactive skipper: same target', () => {
+    // order a,x,b,c; x inactive. a current. nextTurn → b. deact a → b.
+    const x = p('x',7,{ isActive:false });
+    const e = enc([p('a',10),x,p('b',5),p('c',3)], { isStarted:true,
+      turnOrderIds:['a','x','b','c'], currentTurnParticipantId:'a' });
+    const nt = nextTurn(e).patch.currentTurnParticipantId;
+    const deact = toggleParticipantActive(e, 'a').patch.currentTurnParticipantId;
+    expect(deact).toBe(nt);
+    expect(deact).toBe('b');
+  });
+
+  test('wrap: same target + round bump', () => {
+    // order a,b,c. c current. nextTurn → wrap → a (r+1). deact c → wrap → a (r+1).
+    const e = enc([p('a',10),p('b',5),p('c',3)], { isStarted:true,
+      turnOrderIds:['a','b','c'], currentTurnParticipantId:'c', round:2 });
+    const nt = nextTurn(e).patch;
+    const deact = toggleParticipantActive(e, 'c').patch;
+    expect(deact.currentTurnParticipantId).toBe(nt.currentTurnParticipantId);
+    expect(deact.currentTurnParticipantId).toBe('a');
+    expect(deact.round).toBe(nt.round);
+    expect(deact.round).toBe(3);
+  });
+});

shared/tests/turn.invariant.test.js

@@ -0,0 +1,128 @@
+// INVARIANT test: ONE list. turnOrderIds === participants.map(id) always.
+// No re-sort after startEncounter. nextTurn follows list order, skipping inactive.
+// Drag (reorder) overrides initiative — cross-init drag allowed + reflected.
+// Display === rotation by construction (same array).
+//
+// RED now: current code has two lists (sort on display, frozen turnOrderIds),
+// reorder throws on cross-init. Refactor (1-list model) greens these.
+
+'use strict';
+
+const shared = require('@ttrpg/shared');
+const {
+  makeParticipant,
+  startEncounter, nextTurn, addParticipant, removeParticipant,
+  toggleParticipantActive, togglePause, applyHpChange,
+  reorderParticipants, endEncounter,
+} = shared;
+
+function p(id, init, extra = {}) {
+  return makeParticipant({ id, name: id, type: 'monster',
+    initiative: init, maxHp: 100, currentHp: 100, ...extra });
+}
+function enc(ps, extra = {}) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[], ...extra };
+}
+const apply = (e, r) => r && r.patch ? { ...e, ...r.patch } : e;
+
+// walk one full rotation from current, collect active ids in list order
+function walkRotation(e) {
+  if (!e.isStarted || e.isPaused || !e.currentTurnParticipantId) return [];
+  let cur = e;
+  const start = cur.currentTurnParticipantId;
+  const seen = [];
+  for (let i = 0; i < (cur.turnOrderIds || []).length + 1; i++) {
+    const curP = (cur.participants || []).find(p => p.id === cur.currentTurnParticipantId);
+    if (curP && curP.isActive) seen.push(cur.currentTurnParticipantId);
+    const nxt = nextTurn(cur);
+    cur = apply(cur, nxt);
+    if (cur.currentTurnParticipantId === start) break;
+  }
+  return seen;
+}
+
+describe('1-list model: turnOrderIds === participants.map(id), no re-sort', () => {
+  test('startEncounter: list = sorted-active participants order', () => {
+    let e = enc([p('a',3),p('b',10),p('c',5)]);
+    e = apply(e, startEncounter(e));
+    expect(e.turnOrderIds).toEqual(['b','c','a']); // 10,5,3
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
+  });
+
+  test('startEncounter: inactive stays in list slot (skipped by nextTurn)', () => {
+    let e = enc([p('a',10),p('b',5,{isActive:false}),p('c',3)]);
+    e = apply(e, startEncounter(e));
+    // 1-list: inactive b stays in slot, nextTurn skips it
+    expect(e.turnOrderIds).toEqual(['a','b','c']);
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
+    expect(e.currentTurnParticipantId).toBe('a'); // b inactive, skipped on start
+  });
+
+  test('addParticipant mid-encounter: inserted by init, list synced', () => {
+    let e = enc([p('a',10),p('c',3)]);
+    e = apply(e, startEncounter(e)); // [a,c]
+    e = apply(e, addParticipant(e, p('b',7))); // insert between a,c
+    expect(e.turnOrderIds).toEqual(['a','b','c']);
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
+  });
+
+  test('addParticipant: list === participants.map(id) after add', () => {
+    let e = enc([p('a',10)]);
+    e = apply(e, startEncounter(e));
+    e = apply(e, addParticipant(e, p('b',5)));
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
+  });
+
+  test('removeParticipant: list synced, order preserved', () => {
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e));
+    e = apply(e, removeParticipant(e, 'b'));
+    expect(e.turnOrderIds).toEqual(['a','c']);
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
+  });
+
+  test('reorder cross-init: blocked (no-op)', () => {
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e)); // [a,b,c]
+    const r = reorderParticipants(e, 'c', 'a'); // cross-init
+    expect(r.patch).toBeNull();
+    expect(e.turnOrderIds).toEqual(['a','b','c']); // unchanged
+  });
+
+  test('reorder same-init: within upcoming side of pointer follows new order', () => {
+    let e = enc([p('a',10),p('b',10),p('c',10),p('d',3)]); // a,b,c tie
+    e = apply(e, startEncounter(e)); // [a,b,c,d], cur=a (idx0)
+    // Reorder c before b (both upcoming idx1,2). Within same side = allowed.
+    e = apply(e, reorderParticipants(e, 'c', 'b')); // [a,c,b,d], cur=a
+    expect(e.turnOrderIds).toEqual(['a','c','b','d']);
+    // walk: a current, next c, next b, next d, wrap a
+    e = apply(e, nextTurn(e));
+    expect(e.currentTurnParticipantId).toBe('c');
+  });
+
+  test('toggle inactive: list unchanged (stays in rotation slot)', () => {
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e)); // [a,b,c]
+    e = apply(e, toggleParticipantActive(e, 'b')); // b off
+    expect(e.turnOrderIds).toEqual(['a','b','c']); // b stays in slot
+  });
+
+  test('toggle inactive: nextTurn skips b, visits a→c', () => {
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e)); // cur=a
+    e = apply(e, toggleParticipantActive(e, 'b')); // b inactive
+    e = apply(e, nextTurn(e)); // skip b → c
+    expect(e.currentTurnParticipantId).toBe('c');
+  });
+
+  test('hp death + revive: list unchanged', () => {
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e));
+    e = apply(e, applyHpChange(e, 'b', 'damage', 100)); // b dies
+    expect(e.turnOrderIds).toEqual(['a','b','c']);
+    e = apply(e, applyHpChange(e, 'b', 'heal', 50)); // b revive
+    expect(e.turnOrderIds).toEqual(['a','b','c']);
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
+  });
+});

shared/tests/turn.logging.test.js

@@ -0,0 +1,203 @@
+// Logging contract: every mutating combat op returns { patch, log } where
+// log = { message: string, undo: object|null }. No-op (no state change)
+// returns { patch: null, log: null }. Display lifecycle ops return { patch }
+// only (no log field expected).
+//
+// logAction handler does:
+//   if (log) logAction(log.message, ctx, { updates: log.undo })
+// → null log = skipped = gap in audit trail.
+//
+// Contract = every combat mutation MUST produce a log entry.
+
+'use strict';
+
+const shared = require('@ttrpg/shared');
+const {
+  makeParticipant, buildMonsterParticipant,
+  startEncounter, nextTurn, togglePause,
+  addParticipant, addParticipants, updateParticipant, removeParticipant,
+  toggleParticipantActive, applyHpChange, deathSave, toggleCondition,
+  reorderParticipants, endEncounter,
+} = shared;
+
+function p(id, init) {
+  return makeParticipant({ id, name: id, type: 'monster',
+    initiative: init, maxHp: 100, currentHp: 100 });
+}
+function enc(ps, extra = {}) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[], ...extra };
+}
+const apply = (e, r) => r && r.patch ? { ...e, ...r.patch } : e;
+
+// Helper: assert a result is a logged mutation (patch + valid log).
+function expectLogged(r) {
+  expect(r.patch).not.toBeNull();
+  expect(r.log).not.toBeNull();
+  expect(typeof r.log).toBe('object');
+  expect(typeof r.log.message).toBe('string');
+  expect(r.log.message.length).toBeGreaterThan(0);
+}
+function expectNoOp(r) {
+  expect(r.patch).toBeNull();
+  expect(r.log).toBeNull();
+}
+
+describe('Logging contract: mutating ops', () => {
+  let e;
+  beforeEach(() => {
+    e = enc([p('a', 10), p('b', 7), p('c', 3)]);
+  });
+
+  test('startEncounter logs', () => {
+    const r = startEncounter(e);
+    expectLogged(r);
+  });
+
+  test('nextTurn logs', () => {
+    const started = apply(e, startEncounter(e));
+    const r = nextTurn(started);
+    expectLogged(r);
+  });
+
+  test('togglePause logs', () => {
+    const r = togglePause(apply(e, startEncounter(e)));
+    expectLogged(r);
+  });
+
+  test('addParticipant logs', () => {
+    const r = addParticipant(e, p('d', 5));
+    expectLogged(r);
+  });
+
+  test('removeParticipant logs', () => {
+    const r = removeParticipant(e, 'b');
+    expectLogged(r);
+  });
+
+  test('toggleParticipantActive logs', () => {
+    const r = toggleParticipantActive(e, 'b');
+    expectLogged(r);
+  });
+
+  test('applyHpChange (damage) logs', () => {
+    const r = applyHpChange(e, 'b', 'damage', 10);
+    expectLogged(r);
+  });
+
+  test('applyHpChange (heal) logs', () => {
+    const r = applyHpChange(e, 'b', 'heal', 5);
+    expectLogged(r);
+  });
+
+  test('deathSave logs', () => {
+    const started = apply(e, startEncounter(e));
+    const dying = apply(started, applyHpChange(started, 'b', 'damage', 100));
+    const r = deathSave(dying, 'b', 'fail', 1);
+    expectLogged(r);
+  });
+
+  test('toggleCondition logs', () => {
+    const r = toggleCondition(e, 'b', 'poisoned');
+    expectLogged(r);
+  });
+
+  test('reorderParticipants logs (BUG-7)', () => {
+    // same-init tie (both 10) for valid reorder
+    const e2 = enc([p('a', 10), p('x', 10), p('c', 3)]);
+    const r = reorderParticipants(e2, 'x', 'a');
+    expectLogged(r);
+  });
+
+  test('endEncounter logs', () => {
+    const started = apply(e, startEncounter(e));
+    const r = endEncounter(started);
+    expectLogged(r);
+  });
+});
+
+describe('Logging contract: no-ops', () => {
+  let e;
+  beforeEach(() => {
+    e = enc([p('a', 10), p('b', 7), p('c', 3)]);
+  });
+
+  test('reorder same-id = no-op', () => {
+    expectNoOp(reorderParticipants(e, 'a', 'a'));
+  });
+
+  test('reorder cross-init = no-op', () => {
+    expectNoOp(reorderParticipants(e, 'a', 'b'));
+  });
+});
+
+describe('Logging undo payloads', () => {
+  let e;
+  beforeEach(() => {
+    e = enc([p('a', 10), p('b', 7), p('c', 3)]);
+  });
+
+  test('startEncounter undo restores pre-combat state', () => {
+    const r = startEncounter(e);
+    expect(r.log.undo).toBeDefined();
+    expect(r.log.undo.isStarted).toBe(false);
+  });
+
+  test('endEncounter undo restores combat state', () => {
+    const started = apply(e, startEncounter(e));
+    const r = endEncounter(started);
+    expect(r.log.undo).toBeDefined();
+    expect(r.log.undo.isStarted).toBe(true);
+  });
+
+  test('applyHpChange undo restores prior hp', () => {
+    const r = applyHpChange(e, 'b', 'damage', 10);
+    expect(r.log.undo).toBeDefined();
+    expect(r.log.undo.participants).toBeDefined();
+  });
+
+  test('reorder undo restores prior order (BUG-7)', () => {
+    const e2 = enc([p('a', 10), p('x', 10), p('c', 3)]);
+    const orig = e2.participants.map(p => p.id);
+    const r = reorderParticipants(e2, 'x', 'a');
+    expect(r.log.undo).toBeDefined();
+    const restored = { ...e2, ...r.log.undo };
+    expect(restored.participants.map(p => p.id)).toEqual(orig);
+  });
+});
+
+describe('Logging: addParticipants + updateParticipant', () => {
+  let e;
+  beforeEach(() => {
+    e = enc([p('a', 10), p('b', 7)]);
+  });
+
+  test('addParticipants logs', () => {
+    const r = addParticipants(e, [p('c', 3)]);
+    expectLogged(r);
+  });
+
+  test('updateParticipant (same slot) logs', () => {
+    const r = updateParticipant(e, 'b', { name: 'B' });
+    expectLogged(r);
+  });
+
+  test('updateParticipant (init change) logs', () => {
+    const r = updateParticipant(e, 'b', { initiative: 5 });
+    expectLogged(r);
+  });
+
+  test('addParticipants undo restores prior list', () => {
+    const orig = e.participants.map(p => p.id);
+    const r = addParticipants(e, [p('c', 3)]);
+    const restored = { ...e, ...r.log.undo };
+    expect(restored.participants.map(p => p.id)).toEqual(orig);
+  });
+
+  test('updateParticipant undo restores prior participant', () => {
+    const orig = e.participants.map(p => p.id);
+    const r = updateParticipant(e, 'b', { name: 'B' });
+    const restored = { ...e, ...r.log.undo };
+    expect(restored.participants.map(p => p.id)).toEqual(orig);
+  });
+});

shared/tests/turn.pause-add.test.js

@@ -0,0 +1,100 @@
+// Characterization test: addParticipant + pause/resume corrupts turn rotation.
+// Audit found 56-77 violations/100 rounds starting round 20 in pure turn.js
+// simulation. Visible in live replay (round 10: 17 turns, 6 duped actors,
+// R-series stuck repeating forever).
+//
+// This test uses FRESH ids (crypto.randomUUID equivalent) — NOT the audit's
+// self-inflicted dup (loop spun while paused, re-added same `r${totalTurns}`).
+// Validates real bug reachable via normal UI flow (DM adds monster while paused,
+// resumes).
+
+const shared = require('@ttrpg/shared');
+const { startEncounter, nextTurn, togglePause, addParticipant, makeParticipant } = shared;
+
+function p(id, initiative, extra = {}) {
+  return makeParticipant({
+    id, name: id, type: 'monster',
+    initiative, maxHp: 100, currentHp: 100,
+    ...extra,
+  });
+}
+
+function enc(ps) {
+  return {
+    name: 'T', participants: ps,
+    isStarted: false, isPaused: false,
+    round: 0, currentTurnParticipantId: null, turnOrderIds: [],
+  };
+}
+
+describe('addParticipant + pause/resume rotation corruption', () => {
+  test('add fresh participant while paused, resume, rotation completes full cycle', () => {
+    const ps = [p('a', 20), p('b', 15), p('c', 10)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    const baseOrder = e.turnOrderIds.slice(); // [a,b,c]
+
+    e = { ...e, ...nextTurn(e).patch }; // current=b
+    e = { ...e, ...togglePause(e).patch }; // pause
+
+    // add fresh participant x (initiative 25, would sort first)
+    const x = p('x', 25);
+    e = { ...e, ...addParticipant(e, x).patch };
+    e = { ...e, ...togglePause(e).patch }; // resume (rebuilds order)
+
+    // after resume, complete one full round: visit each active participant once
+    const visited = [e.currentTurnParticipantId];
+    for (let i = 0; i < e.turnOrderIds.length - 1; i++) {
+      e = { ...e, ...nextTurn(e).patch };
+      visited.push(e.currentTurnParticipantId);
+    }
+    const uniq = new Set(visited);
+    // EXPECT: 4 unique (a,b,c,x). BUG: rotation may not visit all.
+    expect(uniq.size).toBe(e.turnOrderIds.length);
+  });
+
+  test('multiple adds while paused, resume, rotation visits all', () => {
+    const ps = [p('a', 20), p('b', 15), p('c', 10)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+
+    e = { ...e, ...nextTurn(e).patch }; // current=b
+    e = { ...e, ...togglePause(e).patch }; // pause
+
+    // add 3 fresh participants
+    for (const id of ['x', 'y', 'z']) {
+      const np = p(id, 5 + Math.floor(Math.random() * 30));
+      e = { ...e, ...addParticipant(e, np).patch };
+    }
+    e = { ...e, ...togglePause(e).patch }; // resume
+
+    const visited = [e.currentTurnParticipantId];
+    for (let i = 0; i < e.turnOrderIds.length + 2; i++) {
+      e = { ...e, ...nextTurn(e).patch };
+      visited.push(e.currentTurnParticipantId);
+    }
+    const uniq = new Set(visited);
+    // EXPECT: all 6 participants reachable. BUG: some stuck/repeated.
+    expect(uniq.size).toBe(e.turnOrderIds.length);
+  });
+
+  test('add while running, then pause+resume, rotation stays valid', () => {
+    const ps = [p('a', 20), p('b', 15), p('c', 10)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+
+    e = { ...e, ...nextTurn(e).patch }; // current=b
+    const x = p('x', 25);
+    e = { ...e, ...addParticipant(e, x).patch }; // add while running
+    e = { ...e, ...togglePause(e).patch }; // pause
+    e = { ...e, ...togglePause(e).patch }; // resume
+
+    const visited = [e.currentTurnParticipantId];
+    for (let i = 0; i < e.turnOrderIds.length + 2; i++) {
+      e = { ...e, ...nextTurn(e).patch };
+      visited.push(e.currentTurnParticipantId);
+    }
+    const uniq = new Set(visited);
+    expect(uniq.size).toBe(e.turnOrderIds.length);
+  });
+});

shared/tests/turn.remove.test.js

@@ -0,0 +1,64 @@
+// removeParticipant + computeTurnOrderAfterRemoval edge cases.
+
+const shared = require('@ttrpg/shared');
+const { makeParticipant, startEncounter, nextTurn, removeParticipant, toggleParticipantActive, applyHpChange } = shared;
+
+function p(id, init, extra = {}) {
+  return makeParticipant({ id, name: id, type: 'monster',
+    initiative: init, maxHp: 100, currentHp: 100, ...extra });
+}
+function enc(ps) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[] };
+}
+
+describe('removeParticipant turn-order edges', () => {
+  test('removing current picks next active as current', () => {
+    let e = enc([p('a',20),p('b',15),p('c',10)]);
+    e = { ...e, ...startEncounter(e).patch };
+    e = { ...e, ...removeParticipant(e, 'a').patch }; // a was current
+    expect(e.currentTurnParticipantId).toBe('b');
+  });
+
+  test('removing last in order wraps current to first', () => {
+    let e = enc([p('a',20),p('b',15),p('c',10)]);
+    e = { ...e, ...startEncounter(e).patch };
+    e = { ...e, ...nextTurn(e).patch }; // b
+    e = { ...e, ...nextTurn(e).patch }; // c (current)
+    e = { ...e, ...removeParticipant(e, 'c').patch };
+    expect(e.currentTurnParticipantId).toBe('a');
+  });
+
+  test('removing current when all others inactive → no active, isStarted stays (BUG-9 candidate)', () => {
+    let e = enc([p('a',20),p('b',15),p('c',10)]);
+    e = { ...e, ...startEncounter(e).patch }; // [a,b,c], cur=a
+    // deactivate b + c (stay in slot, inactive)
+    e = { ...e, ...toggleParticipantActive(e, 'b').patch };
+    e = { ...e, ...toggleParticipantActive(e, 'c').patch };
+    // remove current a
+    e = { ...e, ...removeParticipant(e, 'a').patch };
+    // 1-list: turnOrderIds=[b,c], no active → current null, isStarted stays true
+    expect(e.turnOrderIds).toEqual(['b', 'c']);
+    expect(e.currentTurnParticipantId).toBeNull();
+    // isStarted still true but no turn → nextTurn throws (stale state)
+  });
+
+  test('removing non-current keeps currentTurn', () => {
+    let e = enc([p('a',20),p('b',15),p('c',10)]);
+    e = { ...e, ...startEncounter(e).patch };
+    e = { ...e, ...removeParticipant(e, 'b').patch };
+    expect(e.currentTurnParticipantId).toBe('a');
+    expect(e.turnOrderIds).toEqual(['a', 'c']);
+  });
+
+  test('removing current that is dead (HP=0) - BUG-3 overlap', () => {
+    // Dead participant removed mid-combat. Desired (M4): they STAY in order.
+    // removeParticipant is explicit DM action, distinct from auto-skip.
+    let e = enc([p('a',20),p('b',15),p('c',10)]);
+    e = { ...e, ...startEncounter(e).patch };
+    e = { ...e, ...applyHpChange(e, 'b', 'damage', 100).patch }; // b dead
+    e = { ...e, ...removeParticipant(e, 'b').patch };
+    expect(e.turnOrderIds).not.toContain('b');
+    expect(e.participants.find(x => x.id === 'b')).toBeUndefined();
+  });
+});

shared/tests/turn.reorder.test.js

@@ -0,0 +1,65 @@
+// Characterization for reorderParticipants correct usage.
+// replay-combat.js calls it with wrong signature (swallowed by try/catch),
+// so real behavior untested. Lock what it actually does.
+
+const shared = require('@ttrpg/shared');
+const { makeParticipant, startEncounter, nextTurn, reorderParticipants } = shared;
+
+function p(id, init, extra = {}) {
+  return makeParticipant({
+    id, name: id, type: 'monster',
+    initiative: init, maxHp: 100, currentHp: 100,
+    ...extra,
+  });
+}
+function enc(ps) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[] };
+}
+
+describe('reorderParticipants', () => {
+  test('drag before target (1-list model, pre-combat)', () => {
+    const ps = [p('a', 10), p('b', 20), p('c', 20)]; // b,c tie
+    let e = enc(ps); // pre-combat, no pointer
+    const r = reorderParticipants(e, 'c', 'b');
+    // drag c before b: remove c → [a,b], insert before b → [a,c,b]
+    expect(r.patch.participants.map(p => p.id)).toEqual(['a', 'c', 'b']);
+  });
+
+  test('cross-init drag blocked (no-op)', () => {
+    const ps = [p('a', 10), p('b', 20)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch }; // [b,a]
+    const r = reorderParticipants(e, 'a', 'b');
+    expect(r.patch).toBeNull();
+  });
+
+  test('throws if id not found', () => {
+    const ps = [p('a', 10), p('b', 20)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    expect(() => reorderParticipants(e, 'a', 'zzz')).toThrow();
+  });
+
+  test('syncs turnOrderIds = participants order (1-list, fixes BUG-6)', () => {
+    const ps = [p('a', 10), p('b', 20), p('c', 20)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch }; // started, but reorder pre-pointer advance
+    // startEncounter sets current=b (idx0). reorder c before b crosses pointer.
+    // Use pre-combat to test syncTurnOrder.
+    let pre = enc(ps);
+    pre = { ...pre, ...reorderParticipants(pre, 'c', 'b').patch };
+    expect(pre.turnOrderIds).toEqual(['a','c','b']);
+    expect(pre.turnOrderIds).toEqual(pre.participants.map(p => p.id));
+  });
+
+  // BUG-6 candidate: reorder should affect turnOrderIds so mid-combat
+  // drag-drop changes who goes next within same-initiative tie.
+  // Currently RED (turnOrderIds not in patch).
+  test('reorder updates turnOrderIds to reflect new participant order (pre-combat)', () => {
+    const ps = [p('a', 10), p('b', 20), p('c', 20)];
+    let e = enc(ps); // pre-combat, no pointer
+    e = { ...e, ...reorderParticipants(e, 'c', 'b').patch };
+    expect(e.turnOrderIds).toEqual(['a', 'c', 'b']);
+  });
+});

shared/tests/turn.round-rotation.test.js

@@ -0,0 +1,175 @@
+// Regression test: full round must rotate through ALL active participants exactly once.
+// Audit of 100-round replay found 124 skips + 78 dupes (round 1 already missing Fighter
+// before any coverage action). nextTurn has core bug, not just coverage-path issue.
+//
+// This test is RED until nextTurn fixed.
+
+const shared = require('@ttrpg/shared');
+const { startEncounter, nextTurn, makeParticipant } = shared;
+
+function p(id, initiative, extra = {}) {
+  return makeParticipant({
+    id, name: id, type: 'monster',
+    initiative, maxHp: 20, currentHp: 20,
+    ...extra,
+  });
+}
+
+function enc(ps) {
+  return {
+    name: 'T', participants: ps,
+    isStarted: false, isPaused: false,
+    round: 0, currentTurnParticipantId: null, turnOrderIds: [],
+  };
+}
+
+describe('round rotation integrity', () => {
+  test('3 participants: one full round visits each exactly once', () => {
+    const ps = [p('a', 20), p('b', 15), p('c', 10)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+
+    const startOrder = e.turnOrderIds.slice();
+    const visited = [e.currentTurnParticipantId];
+
+    // advance (len-1) turns: visits remaining participants, round NOT yet wrapped.
+    for (let i = 0; i < startOrder.length - 1; i++) {
+      e = { ...e, ...nextTurn(e).patch };
+      visited.push(e.currentTurnParticipantId);
+    }
+
+    expect(e.round).toBe(1); // still round 1
+    const uniq = new Set(visited);
+    expect(uniq.size).toBe(startOrder.length); // each exactly once
+    expect(visited.length).toBe(startOrder.length);
+  });
+
+  test('8 participants (replay shape): one full round visits each exactly once', () => {
+    const ps = [
+      p('Goblin1', 12), p('Wolf', 13), p('Merchant', 8), p('OrcBoss', 11),
+      p('Goblin2', 12), p('Fighter', 14), p('Rogue', 15), p('Cleric', 10),
+    ];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+
+    const startOrder = e.turnOrderIds.slice();
+    const visited = [e.currentTurnParticipantId];
+    for (let i = 0; i < startOrder.length - 1; i++) {
+      e = { ...e, ...nextTurn(e).patch };
+      visited.push(e.currentTurnParticipantId);
+    }
+
+    expect(e.round).toBe(1);
+    const uniq = new Set(visited);
+    expect(uniq.size).toBe(startOrder.length);
+    expect(visited.length).toBe(startOrder.length);
+  });
+
+  test('multiple rounds: each round visits each participant exactly once', () => {
+    const ps = [p('a', 20), p('b', 15), p('c', 10), p('d', 5)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+
+    const startOrder = e.turnOrderIds.slice();
+    const expectedRound = e.round;
+
+    // capture exactly one full round (current + len-1 advances), no wrap yet.
+    const visited = [e.currentTurnParticipantId];
+    for (let i = 0; i < startOrder.length - 1; i++) {
+      e = { ...e, ...nextTurn(e).patch };
+      visited.push(e.currentTurnParticipantId);
+    }
+    const uniq = new Set(visited);
+    expect(uniq.size).toBe(startOrder.length);
+    expect(e.round).toBe(expectedRound);
+  });
+});
+
+describe('round rotation with mid-round state changes', () => {
+  const { toggleParticipantActive, addParticipant, removeParticipant, reorderParticipants, applyHpChange } = shared;
+
+  test('toggle a participant inactive mid-round, others still each visited once', () => {
+    const ps = [p('a', 20), p('b', 15), p('c', 10), p('d', 5)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    const startOrder = e.turnOrderIds.slice();
+
+    const visited = [e.currentTurnParticipantId];
+    e = { ...e, ...nextTurn(e).patch }; visited.push(e.currentTurnParticipantId);
+    // now mark 'a' inactive (already took its turn)
+    e = { ...e, ...toggleParticipantActive(e, 'a').patch };
+    e = { ...e, ...nextTurn(e).patch }; visited.push(e.currentTurnParticipantId);
+    e = { ...e, ...nextTurn(e).patch }; visited.push(e.currentTurnParticipantId);
+    // round should wrap, but 'a' inactive so only b,c,d visited
+    const visitedActive = visited.filter(id => id !== 'a');
+    const uniq = new Set(visitedActive);
+    expect(uniq.size).toBe(startOrder.length - 1); // b,c,d each once
+  });
+
+  test('reactivate inactive participant mid-round, it gets a turn this round', () => {
+    const ps = [p('a', 20), p('b', 15), p('c', 10), p('d', 5)];
+    let e = enc(ps);
+    // start with 'c' inactive
+    e.participants = e.participants.map(p => p.id === 'c' ? { ...p, isActive: false } : p);
+    e = { ...e, ...startEncounter(e).patch };
+    // 1-list: c stays in slot (inactive), skipped by nextTurn
+    expect(e.turnOrderIds).toEqual(['a', 'b', 'c', 'd']);
+    expect(e.currentTurnParticipantId).toBe('a'); // c inactive, a first
+
+    // advance one turn, then reactivate c
+    e = { ...e, ...nextTurn(e).patch }; // b
+    e = { ...e, ...toggleParticipantActive(e, 'c').patch };
+
+    // continue rotation - c should now be reachable
+    const visited = [e.currentTurnParticipantId];
+    for (let i = 0; i < e.turnOrderIds.length; i++) {
+      e = { ...e, ...nextTurn(e).patch };
+      visited.push(e.currentTurnParticipantId);
+    }
+    expect(visited).toContain('c');
+  });
+
+  test('addParticipant mid-round: new participant gets turn this round or next', () => {
+    const ps = [p('a', 20), p('b', 15), p('c', 10)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    const startOrder = e.turnOrderIds.slice();
+
+    e = { ...e, ...nextTurn(e).patch }; // advance one
+    // add new participant
+    const newP = p('x', 25);
+    e = { ...e, ...addParticipant(e, newP).patch };
+
+    // finish round - original 3 should still each get exactly one turn
+    const visited = [startOrder[0], e.currentTurnParticipantId];
+    while (e.round === 1) {
+      const r = nextTurn(e);
+      e = { ...e, ...r.patch };
+      visited.push(e.currentTurnParticipantId);
+      if (visited.length > 20) break; // safety
+    }
+    const originals = visited.filter(id => ['a','b','c'].includes(id));
+    const uniq = new Set(originals);
+    expect(uniq.size).toBe(3);
+  });
+
+  test('reorderParticipants mid-round keeps rotation valid', () => {
+    const ps = [p('a', 20), p('b', 15), p('c', 15), p('d', 5)]; // b,c same init (15)
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    const startOrder = e.turnOrderIds.slice();
+
+    e = { ...e, ...nextTurn(e).patch };
+    // reorder: swap b,c (same initiative)
+    e = { ...e, ...reorderParticipants(e, 'b', 'c').patch };
+
+    const visited = [startOrder[0], e.currentTurnParticipantId];
+    for (let i = 0; i < startOrder.length; i++) {
+      e = { ...e, ...nextTurn(e).patch };
+      visited.push(e.currentTurnParticipantId);
+    }
+    const uniq = new Set(visited);
+    expect(uniq.size).toBeGreaterThanOrEqual(startOrder.length);
+  });
+});
+

shared/tests/turn.skip.test.js

@@ -0,0 +1,122 @@
+// Invariant: no real skip. Every active participant at round start (still
+// active at round end) gets a turn. Tracks per ACTUAL round (e.round), so
+// rounds spanning pause/resume across loop iterations count correctly.
+//
+// Guards BUG-5 fix (slot-array turn order, no re-sort on wrap/resume).
+// If this goes RED, turn order rotation is skipping participants again.
+
+'use strict';
+
+const shared = require('@ttrpg/shared');
+const {
+  buildCharacterParticipant, buildMonsterParticipant,
+  startEncounter, nextTurn, togglePause, addParticipant, removeParticipant,
+  toggleParticipantActive,
+} = shared;
+
+const apply = (e, r) => (r && r.patch) ? { ...e, ...r.patch } : e;
+const nm = (enc) => (id) => {
+  const f = enc.participants.find(p => p.id === id);
+  return f ? f.name : id;
+};
+
+function setup() {
+  const ps = [
+    buildCharacterParticipant({ id: 'c1', name: 'Fighter', defaultMaxHp: 200, defaultInitMod: 2 }).participant,
+    buildCharacterParticipant({ id: 'c2', name: 'Cleric', defaultMaxHp: 180, defaultInitMod: 1 }).participant,
+    buildCharacterParticipant({ id: 'c3', name: 'Rogue', defaultMaxHp: 160, defaultInitMod: 3 }).participant,
+    buildMonsterParticipant({ name: 'Goblin1', maxHp: 100, initMod: 2 }).participant,
+    buildMonsterParticipant({ name: 'Goblin2', maxHp: 100, initMod: 2 }).participant,
+    buildMonsterParticipant({ name: 'OrcBoss', maxHp: 500, initMod: 1 }).participant,
+    buildMonsterParticipant({ name: 'Wolf', maxHp: 120, initMod: 3 }).participant,
+    buildMonsterParticipant({ name: 'Merchant', maxHp: 150, initMod: 0, isNpc: true }).participant,
+  ];
+  let e = {
+    name: 't', participants: ps, isStarted: false, isPaused: false,
+    round: 0, currentTurnParticipantId: null, turnOrderIds: [],
+  };
+  return apply(e, startEncounter(e));
+}
+
+describe('BUG-5: turn-order rotation never skips (deterministic)', () => {
+  jest.setTimeout(15000);
+
+  test('pure nextTurn: 0 skips across 100 rounds', () => {
+    let e = setup();
+    let totalSkips = 0;
+    for (let roundN = 1; roundN <= 100; roundN++) {
+      const startRound = e.round;
+      const activeAtStart = new Set(e.participants.filter(p => p.isActive).map(p => p.id));
+      const acted = new Set();
+      acted.add(e.currentTurnParticipantId);
+      let guard = 0;
+      const cap = e.participants.length + 1;
+      while (e.round === startRound && guard < cap) {
+        e = apply(e, nextTurn(e));
+        if (e.round === startRound) acted.add(e.currentTurnParticipantId);
+        guard++;
+      }
+      const skipped = [...activeAtStart].filter(id => {
+        const p = e.participants.find(x => x.id === id);
+        return p && p.isActive && !acted.has(id);
+      });
+      totalSkips += skipped.length;
+    }
+    expect(totalSkips).toBe(0);
+  });
+
+  test('with pause/resume + add/remove/toggle: 0 skips across ~540 rounds', () => {
+    let e = setup();
+    const N = nm(e);
+    let curRound = null;
+    let activeAtRoundStart = new Set();
+    let actedThisRound = new Set();
+    const onRoundStart = (enc) => {
+      curRound = enc.round;
+      activeAtRoundStart = new Set(enc.participants.filter(p => p.isActive).map(p => p.id));
+      actedThisRound = new Set();
+      if (enc.currentTurnParticipantId) actedThisRound.add(enc.currentTurnParticipantId);
+    };
+    onRoundStart(e);
+
+    let totalRealSkips = 0;
+    let added = 0;
+    let turns = 0;
+    const MAX_TURNS = 2000;
+    while (turns < MAX_TURNS && e.isStarted) {
+      turns++;
+      if (e.isPaused) e = apply(e, togglePause(e));
+      if (turns % 7 === 0 && !e.isPaused) { e = apply(e, togglePause(e)); continue; }
+      const prevRound = e.round;
+      e = apply(e, nextTurn(e));
+      if (e.round !== prevRound) {
+        const skipped = [...activeAtRoundStart].filter(id => {
+          const p = e.participants.find(x => x.id === id);
+          return p && p.isActive && !actedThisRound.has(id);
+        });
+        totalRealSkips += skipped.length;
+        onRoundStart(e);
+      } else {
+        actedThisRound.add(e.currentTurnParticipantId);
+      }
+      if (turns % 9 === 0 && added < 8) {
+        const b = buildMonsterParticipant({ name: `R${added + 1}`, maxHp: 120, initMod: 3 }).participant;
+        b.id = `reinforce${added + 1}`;
+        e = apply(e, addParticipant(e, b)); added++;
+      }
+      if (turns % 13 === 0) {
+        const cand = e.participants.filter(p => p.type === 'monster' && p.isActive && p.id !== e.currentTurnParticipantId);
+        if (cand.length) e = apply(e, removeParticipant(e, cand[0].id));
+      }
+      if (turns % 17 === 0) {
+        const cand = e.participants.filter(p => p.isActive && p.id !== e.currentTurnParticipantId);
+        if (cand.length) {
+          const t = cand[0];
+          e = apply(e, toggleParticipantActive(e, t.id));
+          e = apply(e, toggleParticipantActive(e, t.id));
+        }
+      }
+    }
+    expect(totalRealSkips).toBe(0);
+  });
+});

shared/tests/turn.slot-not-sort.test.js

@@ -0,0 +1,77 @@
+// SLOT-NOT-SORT invariant: addParticipant + updateParticipant must PRESERVE
+// manually-dragged tie order (same-initiative participants).
+//
+// Design doc (docs/INITIATIVE_ORDERING.md):
+//   "Re-slotting on add/edit must preserve drag-established tie order."
+//   "Tie-break = original add order. Later additions slot AFTER existing
+//    same-init participants. Stable insertion."
+//
+// Current code uses sortParticipantsByInitiative (stable sort, tie-break =
+// original array index). That is NOT stable insertion: it re-sorts the whole
+// list, destroying drag order when a drag moved a same-init pair.
+//
+// RED now: drag tie order survives neither add nor edit.
+
+'use strict';
+
+const shared = require('@ttrpg/shared');
+const {
+  makeParticipant,
+  startEncounter, addParticipant, updateParticipant, reorderParticipants,
+} = shared;
+
+function p(id, init, extra = {}) {
+  return makeParticipant({ id, name: id, type: 'monster',
+    initiative: init, maxHp: 100, currentHp: 100, ...extra });
+}
+function enc(ps, extra = {}) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[], ...extra };
+}
+const apply = (e, r) => r && r.patch ? { ...e, ...r.patch } : e;
+
+describe('SLOT-NOT-SORT: drag tie order survives add/edit', () => {
+  test('addParticipant preserves existing drag tie order', () => {
+    // Two same-init participants. DM drags b BEFORE a (tie override).
+    let e = enc([p('a', 10), p('b', 10)]);
+    e = apply(e, reorderParticipants(e, 'b', 'a')); // drag b ahead of a → [b,a]
+    expect(e.participants.map(x => x.id)).toEqual(['b', 'a']);
+
+    // Add unrelated participant (different init). Tie order [b,a] MUST survive.
+    e = apply(e, addParticipant(e, p('c', 5)));
+    const ids = e.participants.map(x => x.id);
+    // c slots last (init 5 < 10). b,a tie order preserved.
+    expect(ids).toEqual(['b', 'a', 'c']);
+  });
+
+  test('addParticipant with same init as dragged pair slots AFTER tie group', () => {
+    // DM drags b before a (both init 10). Then add d also init 10.
+    // d must slot AFTER existing same-init pair (stable insertion), not re-sort.
+    let e = enc([p('a', 10), p('b', 10)]);
+    e = apply(e, reorderParticipants(e, 'b', 'a')); // [b,a]
+    e = apply(e, addParticipant(e, p('d', 10))); // init 10, after tie group
+    const ids = e.participants.map(x => x.id);
+    expect(ids).toEqual(['b', 'a', 'd']);
+  });
+
+  test('updateParticipant preserves drag tie order on unrelated field edit', () => {
+    let e = enc([p('a', 10), p('b', 10)]);
+    e = apply(e, reorderParticipants(e, 'b', 'a')); // [b,a]
+    // Edit a's name (not initiative). Tie order MUST survive.
+    e = apply(e, updateParticipant(e, 'a', { name: 'A2' }));
+    expect(e.participants.map(x => x.id)).toEqual(['b', 'a']);
+  });
+
+  test('updateParticipant init change slots, preserves OTHER tie group order', () => {
+    // Two tie groups: [a,b] init 10, [c,d] init 5. DM drags b before a.
+    let e = enc([p('a', 10), p('b', 10), p('c', 5), p('d', 5)]);
+    e = apply(e, reorderParticipants(e, 'b', 'a')); // [b,a,c,d]
+    // Edit c's initiative to 10 — slots into top group. [c] order within its
+    // own old group irrelevant (it leaves that group). But [b,a] tie MUST stay.
+    e = apply(e, updateParticipant(e, 'c', { initiative: 10 }));
+    const topTwo = e.participants.filter(x => x.initiative === 10).map(x => x.id);
+    // b before a preserved. c joins the 10-group (exact slot less critical
+    // than b,a order surviving).
+    expect(topTwo.indexOf('b')).toBeLessThan(topTwo.indexOf('a'));
+  });
+});

shared/tests/turn.undo.test.js

@@ -0,0 +1,130 @@
+// Undo roundtrip: every op that returns log.undo must restore prior state.
+// Apply op → patch → apply undo → assert deepEqual original.
+
+const shared = require('@ttrpg/shared');
+const {
+  makeParticipant, startEncounter, nextTurn, togglePause,
+  addParticipant, removeParticipant, toggleParticipantActive,
+  applyHpChange, toggleCondition, reorderParticipants, endEncounter,
+} = shared;
+
+function p(id, init, extra = {}) {
+  return makeParticipant({
+    id, name: id, type: 'monster',
+    initiative: init, maxHp: 100, currentHp: 100,
+    ...extra,
+  });
+}
+function enc(ps) {
+  return { name:'t', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[] };
+}
+const snap = (e) => JSON.parse(JSON.stringify(e));
+
+describe('undo roundtrip', () => {
+  test('startEncounter undo restores pre-start', () => {
+    const before = enc([p('a',10),p('b',20)]);
+    const r = startEncounter(before);
+    expect(r.log.undo).toBeTruthy();
+    // undo restores isStarted/isPaused/round/current/turnOrderIds.
+    // participants[] may be reordered (1-list sort on start) — undo snapshot
+    // captures turn-state fields, not participant order.
+    const after = { ...before, ...r.patch, ...r.log.undo };
+    expect(after.isStarted).toBe(before.isStarted);
+    expect(after.isPaused).toBe(before.isPaused);
+    expect(after.round).toBe(before.round);
+    expect(after.currentTurnParticipantId).toBe(before.currentTurnParticipantId);
+    expect(after.turnOrderIds).toEqual(before.turnOrderIds);
+  });
+
+  test('nextTurn undo restores prior currentTurn/round', () => {
+    let e = enc([p('a',10),p('b',20),p('c',5)]);
+    e = { ...e, ...startEncounter(e).patch };
+    const before = snap(e);
+    const r = nextTurn(e);
+    expect(r.log.undo).toBeTruthy();
+    const after = { ...e, ...r.patch, ...r.log.undo };
+    expect(snap(after)).toEqual(before);
+  });
+
+  test('togglePause undo restores prior paused state', () => {
+    let e = enc([p('a',10),p('b',20)]);
+    e = { ...e, ...startEncounter(e).patch };
+    const before = snap(e);
+    const r = togglePause(e);
+    expect(r.log.undo).toBeTruthy();
+    const after = { ...e, ...r.patch, ...r.log.undo };
+    expect(snap(after)).toEqual(before);
+  });
+
+  test('applyHpChange undo restores prior participants', () => {
+    let e = enc([p('a',10,{maxHp:100,currentHp:100}),p('b',20)]);
+    e = { ...e, ...startEncounter(e).patch };
+    const before = snap(e);
+    const r = applyHpChange(e, 'a', 'damage', 20);
+    expect(r.log.undo).toBeTruthy();
+    const after = { ...e, ...r.patch, ...r.log.undo };
+    expect(snap(after)).toEqual(before);
+  });
+
+  test('toggleCondition undo restores prior participants', () => {
+    let e = enc([p('a',10),p('b',20)]);
+    e = { ...e, ...startEncounter(e).patch };
+    const before = snap(e);
+    const r = toggleCondition(e, 'a', 'stunned');
+    expect(r.log.undo).toBeTruthy();
+    const after = { ...e, ...r.patch, ...r.log.undo };
+    expect(snap(after)).toEqual(before);
+  });
+
+  test('toggleParticipantActive undo restores prior participants + turn order', () => {
+    let e = enc([p('a',10),p('b',20),p('c',5)]);
+    e = { ...e, ...startEncounter(e).patch };
+    const before = snap(e);
+    const r = toggleParticipantActive(e, 'b');
+    expect(r.log.undo).toBeTruthy();
+    const after = { ...e, ...r.patch, ...r.log.undo };
+    expect(snap(after)).toEqual(before);
+  });
+
+  test('addParticipant undo restores prior participants', () => {
+    let e = enc([p('a',10),p('b',20)]);
+    e = { ...e, ...startEncounter(e).patch };
+    const before = snap(e);
+    const np = makeParticipant({ id:'z', name:'z', type:'monster', initiative:15, maxHp:50, currentHp:50 });
+    const r = addParticipant(e, np);
+    expect(r.log.undo).toBeTruthy();
+    const after = { ...e, ...r.patch, ...r.log.undo };
+    expect(snap(after)).toEqual(before);
+  });
+
+  test('removeParticipant undo restores prior participants + turn order', () => {
+    let e = enc([p('a',10),p('b',20),p('c',5)]);
+    e = { ...e, ...startEncounter(e).patch };
+    const before = snap(e);
+    const r = removeParticipant(e, 'b');
+    expect(r.log.undo).toBeTruthy();
+    const after = { ...e, ...r.patch, ...r.log.undo };
+    expect(snap(after)).toEqual(before);
+  });
+
+  test('endEncounter undo restores prior state', () => {
+    let e = enc([p('a',10),p('b',20)]);
+    e = { ...e, ...startEncounter(e).patch };
+    const before = snap(e);
+    const r = endEncounter(e);
+    expect(r.log.undo).toBeTruthy();
+    const after = { ...e, ...r.patch, ...r.log.undo };
+    expect(snap(after)).toEqual(before);
+  });
+
+  test('reorderParticipants has no undo (log: null) — BUG candidate', () => {
+    const ps = [p('a',10),p('b',20),p('c',20)]; // b,c tie
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    const r = reorderParticipants(e, 'c', 'b');
+    // Documents: reorderParticipants returns log: null. Cannot undo.
+    // If undo expected here, this is BUG-7.
+    expect(r.log).toBeNull();
+  });
+});

shared/turn.js

@@ -0,0 +1,700 @@
+// @ttrpg/shared — turn.js
+// Pure turn-order logic. No I/O, no React, no Firebase.
+// Ported VERBATIM from src/App.js (M1). Bugs preserved intentionally.
+// Characterization tests lock current behavior. Fixes come in M4.
+//
+// Functions return NEW state (immutable). They never mutate input encounter.
+
+'use strict';
+
+// ----------------------------------------------------------------------------
+// Constants (mirror src/App.js)
+// ----------------------------------------------------------------------------
+
+const DEFAULT_MAX_HP = 10;
+const DEFAULT_INIT_MOD = 0;
+const MONSTER_DEFAULT_INIT_MOD = 2;
+
+// ----------------------------------------------------------------------------
+// Utility functions (verbatim from src/App.js)
+// ----------------------------------------------------------------------------
+
+const generateId = () =>
+  (typeof crypto !== 'undefined' && crypto.randomUUID)
+    ? crypto.randomUUID()
+    : `id_${Date.now()}_${Math.random().toString(36).slice(2, 10)}`;
+
+const rollD20 = () => Math.floor(Math.random() * 20) + 1;
+
+const formatInitMod = (mod) => {
+  if (mod === undefined || mod === null) return 'N/A';
+  return mod >= 0 ? `+${mod}` : `${mod}`;
+};
+
+// SLOT, NEVER SORT. 1-list model (docs/INITIATIVE_ORDERING.md).
+//
+// `sortParticipantsByInitiative` exists for ONE call site: startEncounter
+// (freeze list once by init). After that, mutations = insert/move ops that
+// PRESERVE existing array order. No wholesale re-sort ever — destroys drag
+// tie-break order.
+//
+// slotIndexForInit: pure insert position. Scans existing list, returns index
+// of first participant with init STRICTLY LESS than target. New participant
+// splices there. Same-init participants stay ahead (stable). Existing tie
+// order (incl. drag-established) untouched because scan reads current array,
+// not original add-order.
+const sortParticipantsByInitiative = (participants, originalOrder) => {
+  return [...participants].sort((a, b) => {
+    if (a.initiative === b.initiative) {
+      const indexA = originalOrder.findIndex(p => p.id === a.id);
+      const indexB = originalOrder.findIndex(p => p.id === b.id);
+      return indexA - indexB;
+    }
+    return b.initiative - a.initiative;
+  });
+};
+
+// Find splice index for a single participant by initiative. List assumed
+// already initiative-descending (startEncounter freezes it; add/edit maintain).
+// Returns position to insert so list stays descending, ties go AFTER existing
+// same-init (stable insertion). Current array order = source of truth.
+function slotIndexForInit(list, init) {
+  for (let i = 0; i < list.length; i++) {
+    if (init > list[i].initiative) return i;
+  }
+  return list.length;
+}
+
+// 1-LIST SYNC: turnOrderIds always mirrors participants[].map(id).
+// Call after any participants[] mutation. Returns turnOrderIds patch.
+const syncTurnOrder = (participants) => ({
+  turnOrderIds: participants.map(p => p.id),
+});
+
+// SHARED ADVANCE CORE (BUG-5 DRY fix).
+// Single source of truth for "who acts next". Both nextTurn and
+// computeTurnOrderAfterRemoval delegate here — prevents drift where one path
+// changes and the other doesn't.
+//
+// order: turnOrderIds (raw, may contain inactive/removed ids).
+// fromPos: index of the last-acted slot (current participant, or the removed
+//   participant's old slot). Step +1 forward, skip fromPos itself.
+// isActive: predicate id -> bool.
+// Returns { nextId, wrapped }. wrapped = cycled past order end = new round.
+const nextActiveAfter = (order, fromPos, isActive) => {
+  const n = order.length;
+  if (n === 0) return { nextId: null, wrapped: false };
+  for (let step = 1; step < n; step++) {
+    const idx = (fromPos + step) % n;
+    const id = order[idx];
+    if (isActive(id)) return { nextId: id, wrapped: idx <= fromPos };
+  }
+  return { nextId: null, wrapped: false }; // no other active participant
+};
+
+// Verbatim from src/App.js. Returns turnOrderIds/currentTurnParticipantId updates
+// when a participant leaves active combat.
+const computeTurnOrderAfterRemoval = (encounter, removedId, updatedParticipants) => {
+  if (!encounter.isStarted) return {};
+  // 1-list: turnOrderIds syncs from participants[].map(id) at call site.
+  // Here only handle current-advance if removed == current.
+  const updates = {};
+  if (encounter.currentTurnParticipantId === removedId) {
+    const removedPos = (encounter.turnOrderIds || []).indexOf(removedId);
+    const isActive = id => updatedParticipants.find(p => p.id === id && p.isActive);
+    const { nextId, wrapped } = nextActiveAfter(encounter.turnOrderIds || [], removedPos, isActive);
+    updates.currentTurnParticipantId = nextId;
+    if (nextId && wrapped) updates.round = (encounter.round || 1) + 1;
+  }
+  return updates;
+};
+
+// Insert addedId into turnOrderIds by initiative. New participant slots into
+// correct initiative position at add time (not appended to end). Preserves
+// current pointer — no re-sort anywhere except startEncounter.
+// Tie rule: insert AFTER existing same-init (preserves creation order).
+// NOTE: 1-list model — caller syncs participants[] in same pos as insert target.
+// Participant factory (mirrors ParticipantManager.handleAddParticipant shape)
+// ----------------------------------------------------------------------------
+
+function makeParticipant(opts) {
+  return {
+    id: opts.id || generateId(),
+    name: opts.name,
+    type: opts.type, // 'character' | 'monster'
+    originalCharacterId: opts.originalCharacterId || null,
+    initiative: opts.initiative,
+    maxHp: opts.maxHp,
+    currentHp: opts.currentHp,
+    isNpc: opts.isNpc || false,
+    conditions: opts.conditions || [],
+    isActive: opts.isActive !== undefined ? opts.isActive : true,
+    deathSaves: opts.deathSaves || 0,  // successes (0-3)
+    deathFails: opts.deathFails || 0,  // failures (0-3)
+    isStable: opts.isStable || false,
+    isDying: opts.isDying || false,
+  };
+}
+
+// Build a character participant from a campaign character (rolls initiative).
+function buildCharacterParticipant(character) {
+  const initiativeRoll = rollD20();
+  const modifier = character.defaultInitMod || 0;
+  const finalInitiative = initiativeRoll + modifier;
+  const maxHp = character.defaultMaxHp || DEFAULT_MAX_HP;
+  return {
+    participant: makeParticipant({
+      name: character.name,
+      type: 'character',
+      originalCharacterId: character.id,
+      initiative: finalInitiative,
+      maxHp,
+      currentHp: maxHp,
+      isNpc: false,
+    }),
+    roll: { roll: initiativeRoll, mod: modifier, total: finalInitiative },
+  };
+}
+
+// Build a monster participant (rolls initiative).
+function buildMonsterParticipant({ name, maxHp, initMod, isNpc }) {
+  const initiativeRoll = rollD20();
+  const modifier = initMod !== undefined ? initMod : MONSTER_DEFAULT_INIT_MOD;
+  const finalInitiative = initiativeRoll + modifier;
+  const hp = maxHp || DEFAULT_MAX_HP;
+  return {
+    participant: makeParticipant({
+      name,
+      type: 'monster',
+      initiative: finalInitiative,
+      maxHp: hp,
+      currentHp: hp,
+      isNpc: isNpc || false,
+    }),
+    roll: { roll: initiativeRoll, mod: modifier, total: finalInitiative },
+  };
+}
+
+// ----------------------------------------------------------------------------
+// Action handlers — pure: (encounter, action) => { encounter, patch, log }
+// Return patch = partial fields to merge into stored encounter.
+// Caller persists patch + broadcasts.
+// ----------------------------------------------------------------------------
+
+// START_ENCOUNTER — verbatim from InitiativeControls.handleStartEncounter
+function startEncounter(encounter) {
+  if (!encounter.participants || encounter.participants.length === 0) {
+    throw new Error('Add participants first.');
+  }
+  // 1-list model: sort ALL participants by init (active + inactive) so display
+  // order = initiative. nextTurn skips inactive. turnOrderIds mirrors list.
+  const sortedParticipants = sortParticipantsByInitiative(encounter.participants || [], encounter.participants);
+  const firstActive = sortedParticipants.find(p => p.isActive);
+  if (!firstActive) {
+    throw new Error('No active participants.');
+  }
+  const orderedParticipants = sortedParticipants;
+  return {
+    patch: {
+      isStarted: true,
+      isPaused: false,
+      round: 1,
+      participants: orderedParticipants,
+      currentTurnParticipantId: firstActive.id,
+      turnOrderIds: orderedParticipants.map(p => p.id),
+    },
+    log: {
+      message: `Combat started: "${encounter.name}" — ${firstActive.name}'s turn (Round 1)`,
+      undo: {
+        isStarted: encounter.isStarted ?? false,
+        isPaused: encounter.isPaused ?? false,
+        round: encounter.round ?? 0,
+        currentTurnParticipantId: encounter.currentTurnParticipantId ?? null,
+        turnOrderIds: [...(encounter.turnOrderIds || [])],
+      },
+    },
+  };
+}
+
+// NEXT_TURN — verbatim from InitiativeControls.handleNextTurn
+// NOTE: this is the suspected skip-bug source. Preserved for M3 characterization.
+function nextTurn(encounter) {
+  if (!encounter.isStarted || encounter.isPaused) {
+    throw new Error('Encounter not running.');
+  }
+  if (!encounter.currentTurnParticipantId || !encounter.turnOrderIds || encounter.turnOrderIds.length === 0) {
+    throw new Error('No active turn.');
+  }
+
+  const activePsInOrder = encounter.turnOrderIds
+    .map(id => encounter.participants.find(p => p.id === id && p.isActive))
+    .filter(Boolean);
+
+  if (activePsInOrder.length === 0) {
+    // End encounter — no active participants left.
+    return {
+      patch: {
+        isStarted: false,
+        isPaused: false,
+        currentTurnParticipantId: null,
+        round: encounter.round,
+      },
+      log: { message: `Combat auto-ended: no active participants`, undo: null },
+    };
+  }
+
+  let nextRound = encounter.round;
+  let newTurnOrderIds = encounter.turnOrderIds;
+
+  // Delegate to shared advance core (BUG-5 DRY fix). Same math
+  // computeTurnOrderAfterRemoval uses → no drift. fromPos = current's slot
+  // in raw turnOrderIds; -1 path handles removed/stale current.
+  const order = encounter.turnOrderIds || [];
+  const fromPos = order.indexOf(encounter.currentTurnParticipantId);
+  const isActive = id => {
+    const p = encounter.participants.find(x => x.id === id);
+    return !!p && p.isActive;
+  };
+  const { nextId, wrapped } = nextActiveAfter(order, fromPos, isActive);
+
+  if (!nextId) {
+    throw new Error('Could not determine next participant.');
+  }
+  if (wrapped) nextRound += 1;
+
+  const nextParticipant = encounter.participants.find(p => p.id === nextId);
+
+  return {
+    patch: {
+      currentTurnParticipantId: nextParticipant.id,
+      round: nextRound,
+      turnOrderIds: newTurnOrderIds,
+    },
+    log: {
+      message: `${nextParticipant.name}'s turn (Round ${nextRound})`,
+      undo: {
+        currentTurnParticipantId: encounter.currentTurnParticipantId,
+        round: encounter.round,
+        turnOrderIds: [...encounter.turnOrderIds],
+      },
+    },
+  };
+}
+
+// PAUSE / RESUME — verbatim from InitiativeControls.handleTogglePause
+function togglePause(encounter) {
+  if (!encounter || !encounter.isStarted) {
+    throw new Error('Encounter not started.');
+  }
+  const newPausedState = !encounter.isPaused;
+  let newTurnOrderIds = encounter.turnOrderIds;
+  if (!newPausedState && encounter.isPaused) {
+    // Resume: do NOT re-sort. Re-sorting displaces the current pointer —
+    // participants who already acted move earlier in order and nextTurn
+    // revisits them (whole round replays). Order is frozen at startEncounter
+    // and patched incrementally; resume keeps it stable.
+  }
+  return {
+    patch: { isPaused: newPausedState, turnOrderIds: newTurnOrderIds },
+    log: {
+      message: `Combat ${newPausedState ? 'paused' : 'resumed'}: "${encounter.name}"`,
+      undo: {
+        isPaused: encounter.isPaused ?? false,
+        turnOrderIds: [...(encounter.turnOrderIds || [])],
+      },
+    },
+  };
+}
+
+// ADD_PARTICIPANT — appends participant. (Initiative rolled by caller via build*.)
+// If encounter already started, also slot participant into turnOrderIds by
+// initiative (slotIndexForInit). 1-list model.
+function addParticipant(encounter, participant) {
+  if ((encounter.participants || []).some(p => p.id === participant.id)) {
+    throw new Error(`Participant with id "${participant.id}" already exists in encounter.`);
+  }
+  // SLOT (not sort): insert by initiative into current list. Preserves
+  // existing array order incl. drag-established tie order.
+  const base = [...(encounter.participants || [])];
+  const idx = slotIndexForInit(base, participant.initiative);
+  base.splice(idx, 0, participant);
+  const updatedParticipants = base;
+  return {
+    patch: { participants: updatedParticipants, ...syncTurnOrder(updatedParticipants) },
+    log: {
+      message: `${participant.name} added to encounter (Initiative: ${participant.initiative})`,
+      undo: {
+        participants: [...(encounter.participants || [])],
+        ...(encounter.isStarted ? {
+          turnOrderIds: [...(encounter.turnOrderIds || [])],
+        } : {}),
+      },
+    },
+  };
+}
+
+// ADD_PARTICIPANTS — bulk add (e.g. "add all campaign characters").
+function addParticipants(encounter, newParticipants) {
+  const undo = { participants: encounter.participants || [] };
+  const updatedParticipants = [...(encounter.participants || []), ...newParticipants];
+  const names = newParticipants.map(p => p.name).join(', ');
+  return {
+    patch: { participants: updatedParticipants },
+    log: {
+      message: `Added ${newParticipants.length} participant${newParticipants.length === 1 ? '' : 's'}: ${names}`,
+      undo,
+    },
+  };
+}
+
+// UPDATE_PARTICIPANT — edit modal save (name/initiative/hp/isNpc).
+function updateParticipant(encounter, participantId, updatedData) {
+  const existing = encounter.participants || [];
+  const target = existing.find(p => p.id === participantId);
+  if (!target) throw new Error(`Participant "${participantId}" not found.`);
+  const merged = { ...target, ...updatedData };
+  // SLOT only if initiative changed. Other edits (name/hp/notes/isNpc) = no
+  // position change (design doc). Re-slots on unrelated edits shuffle the
+  // list mid-round → rotation dupes.
+  const undo = { participants: encounter.participants || [] };
+  if (!('initiative' in updatedData) || updatedData.initiative === target.initiative) {
+    const sameSlot = existing.map(p => p.id === participantId ? merged : p);
+    const fields = Object.keys(updatedData).join(', ');
+    return {
+      patch: { participants: sameSlot, ...syncTurnOrder(sameSlot) },
+      log: {
+        message: `${target.name} updated (${fields})`,
+        undo,
+      },
+    };
+  }
+  const without = existing.filter(p => p.id !== participantId);
+  const idx = slotIndexForInit(without, merged.initiative);
+  without.splice(idx, 0, merged);
+  return {
+    patch: { participants: without, ...syncTurnOrder(without) },
+    log: {
+      message: `${target.name} updated (initiative: ${merged.initiative})`,
+      undo,
+    },
+  };
+}
+
+// REMOVE_PARTICIPANT — verbatim from ParticipantManager.confirmDeleteParticipant
+function removeParticipant(encounter, participantId) {
+  const updatedParticipants = (encounter.participants || []).filter(p => p.id !== participantId);
+  const advUpdates = computeTurnOrderAfterRemoval(encounter, participantId, updatedParticipants);
+  const turnUpdates = encounter.isStarted ? { ...syncTurnOrder(updatedParticipants), ...advUpdates } : {};
+  const participant = (encounter.participants || []).find(p => p.id === participantId);
+  return {
+    patch: { participants: updatedParticipants, ...turnUpdates },
+    log: {
+      message: `${participant ? participant.name : 'Participant'} removed from encounter`,
+      undo: {
+        participants: [...(encounter.participants || [])],
+        ...(encounter.isStarted ? {
+          currentTurnParticipantId: encounter.currentTurnParticipantId,
+          turnOrderIds: [...(encounter.turnOrderIds || [])],
+        } : {}),
+      },
+    },
+  };
+}
+
+// TOGGLE_ACTIVE — verbatim from ParticipantManager.toggleParticipantActive
+function toggleParticipantActive(encounter, participantId) {
+  const participant = (encounter.participants || []).find(p => p.id === participantId);
+  if (!participant) throw new Error('Participant not found.');
+  const newIsActive = !participant.isActive;
+  const updatedParticipants = (encounter.participants || []).map(p =>
+    p.id === participantId ? { ...p, isActive: newIsActive } : p
+  );
+  // 1-list: participant stays in slot on toggle (active or not). nextTurn
+  // skips inactive. Only advance current if deact hits current.
+  let turnUpdates = {};
+  if (encounter.isStarted) {
+    turnUpdates = syncTurnOrder(updatedParticipants);
+    if (!newIsActive && encounter.currentTurnParticipantId === participantId) {
+      const adv = computeTurnOrderAfterRemoval(encounter, participantId, updatedParticipants);
+      turnUpdates = { ...turnUpdates, ...adv };
+    }
+  }
+  return {
+    patch: { participants: updatedParticipants, ...turnUpdates },
+    log: {
+      message: `${participant.name} ${newIsActive ? 'reactivated' : 'deactivated'}`,
+      undo: {
+        participants: [...(encounter.participants || [])],
+        ...(encounter.isStarted ? {
+          currentTurnParticipantId: encounter.currentTurnParticipantId,
+          turnOrderIds: [...(encounter.turnOrderIds || [])],
+        } : {}),
+      },
+    },
+  };
+}
+
+// APPLY_HP_CHANGE — verbatim from ParticipantManager.applyHpChange
+// changeType: 'damage' | 'heal'
+function applyHpChange(encounter, participantId, changeType, amount) {
+  const participant = (encounter.participants || []).find(p => p.id === participantId);
+  if (!participant) throw new Error('Participant not found.');
+  if (isNaN(amount) || amount === 0) {
+    return { patch: null, log: null }; // no-op
+  }
+  let newHp = participant.currentHp;
+  if (changeType === 'damage') newHp = Math.max(0, participant.currentHp - amount);
+  else if (changeType === 'heal') newHp = Math.min(participant.maxHp, participant.currentHp + amount);
+
+  const wasDead = participant.currentHp === 0;
+  const isDead = newHp === 0;
+  const wasResurrected = wasDead && newHp > 0;
+
+  // Unified (App main): death flips isActive=false (removed from active
+  // rotation, skipped by nextTurn). Revive flips true. No turnOrderIds change.
+  const updatedParticipants = (encounter.participants || []).map(p => {
+    if (p.id !== participantId) return p;
+    const updates = { ...p, currentHp: newHp };
+    if (isDead && !wasDead) {
+      updates.isActive = false;
+      updates.deathSaves = p.deathSaves || 0;
+      updates.isDying = false;
+    }
+    if (wasResurrected) {
+      updates.isActive = true;
+      updates.deathSaves = 0;
+      updates.isDying = false;
+    }
+    return updates;
+  });
+
+  const turnUpdates = {};
+
+  const hpLine = `${participant.currentHp} → ${newHp} HP`;
+  const deathSuffix = (isDead && !wasDead)
+    ? (participant.type === 'character' ? ' — Unconscious' : ' — Defeated')
+    : '';
+  const resurSuffix = wasResurrected ? ' — Revived' : '';
+  const message = changeType === 'damage'
+    ? `${participant.name} took ${amount} damage (${hpLine})${deathSuffix}`
+    : `${participant.name} healed for ${amount} (${hpLine})${resurSuffix}`;
+
+  return {
+    patch: { participants: updatedParticipants, ...turnUpdates },
+    log: {
+      message,
+      undo: {
+        participants: [...(encounter.participants || [])],
+        ...((isDead && !wasDead) || wasResurrected ? {
+          currentTurnParticipantId: encounter.currentTurnParticipantId,
+          turnOrderIds: [...(encounter.turnOrderIds || [])],
+        } : {}),
+      },
+    },
+  };
+}
+
+// DEATH_SAVE — D&D 5e model. Separate success/fail tracking.
+//   type: 'success' | 'fail'
+//   n: 1 | 2 | 3 (which pip clicked)
+// 3 successes = stable (0hp unconscious, safe). 3 fails = dead (isDying,
+//   caller animates removal). Toggling same pip = undo that pip.
+// Returns { patch, log, status } where status: 'stable'|'dead'|'pending'.
+function deathSave(encounter, participantId, type, n) {
+  const participant = (encounter.participants || []).find(p => p.id === participantId);
+  if (!participant) throw new Error('Participant not found.');
+  if (type !== 'success' && type !== 'fail') {
+    throw new Error(`deathSave type must be 'success' or 'fail', got "${type}".`);
+  }
+  const name = participant.name;
+  const undo = { participants: encounter.participants || [] };
+
+  // Toggle: clicking current-value pip decrements (undo that pip).
+  const current = type === 'success'
+    ? (participant.deathSaves || 0)
+    : (participant.deathFails || 0);
+  const next = current === n ? n - 1 : n;
+
+  const field = type === 'success' ? 'deathSaves' : 'deathFails';
+  const updates = { [field]: next };
+
+  // Clear terminal flags on any change (re-eval below).
+  let status = 'pending';
+  const newSuccesses = type === 'success' ? next : (participant.deathSaves || 0);
+  const newFails = type === 'fail' ? next : (participant.deathFails || 0);
+
+  if (newSuccesses >= 3) {
+    updates.isStable = true;
+    updates.isDying = false;
+    status = 'stable';
+  } else if (newFails >= 3) {
+    updates.isStable = false;
+    updates.isDying = true;
+    status = 'dead';
+  } else {
+    updates.isStable = false;
+    updates.isDying = false;
+  }
+
+  const updatedParticipants = (encounter.participants || []).map(p =>
+    p.id === participantId ? { ...p, ...updates } : p
+  );
+
+  const message = status === 'stable'
+    ? `${name} stabilized (3 death saves)`
+    : status === 'dead'
+      ? `${name} failed 3 death saves — dead`
+      : `${name} death ${type}: ${next}/3`;
+
+  return {
+    patch: { participants: updatedParticipants },
+    log: { message, undo },
+    status,
+    isDying: status === 'dead', // back-compat for App.js handler
+  };
+}
+
+// TOGGLE_CONDITION — verbatim from ParticipantManager.toggleCondition
+function toggleCondition(encounter, participantId, conditionId) {
+  const participant = (encounter.participants || []).find(p => p.id === participantId);
+  if (!participant) throw new Error('Participant not found.');
+  const wasActive = (participant.conditions || []).includes(conditionId);
+  const updatedParticipants = (encounter.participants || []).map(p => {
+    if (p.id !== participantId) return p;
+    const current = p.conditions || [];
+    const next = wasActive ? current.filter(c => c !== conditionId) : [...current, conditionId];
+    return { ...p, conditions: next };
+  });
+  return {
+    patch: { participants: updatedParticipants },
+    log: {
+      message: `${participant.name} ${wasActive ? 'lost' : 'gained'} ${conditionId}`,
+      undo: { participants: [...(encounter.participants || [])] },
+    },
+  };
+}
+
+// REORDER_PARTICIPANTS — drag. Same-initiative ONLY (tie-break override).
+// Cross-init drag = no-op (use edit-initiative field instead). Splice move.
+// Cross-pointer drag = no-op once encounter started (BUG-13). nextTurn walks
+// turnOrderIds forward from current pointer. Dragging a not-yet-acted
+// participant to a position behind the pointer would skip them (wrap past).
+// Dragging an already-acted participant ahead of pointer would re-act them.
+// Blocking cross-pointer keeps rotation deterministic. Pre-combat: free.
+function reorderParticipants(encounter, draggedId, targetId) {
+  const participants = [...(encounter.participants || [])];
+  const dragged = participants.find(p => p.id === draggedId);
+  const target = participants.find(p => p.id === targetId);
+  if (!dragged || !target) throw new Error('Dragged or target item not found.');
+  if (draggedId === targetId) return { patch: null, log: null };
+  if (dragged.initiative !== target.initiative) {
+    return { patch: null, log: null }; // cross-init blocked
+  }
+  const draggedIndex = participants.findIndex(p => p.id === draggedId);
+  // BUG-13: block cross-pointer reorder while encounter running. nextTurn
+  // walks turnOrderIds forward from current pointer. Dragging across the
+  // pointer makes who-acts-next ambiguous — either skip (upcoming dragged
+  // ahead of pointer, walk wraps past) or double-act (acted dragged behind).
+  // Full fix needs actedThisRound tracking. Pragmatic now: block both dirs.
+  // Pre-combat: free reorder (no pointer yet).
+  if (encounter.isStarted && encounter.currentTurnParticipantId) {
+    const pointerIdx = participants.findIndex(p => p.id === encounter.currentTurnParticipantId);
+    const targetIdx0 = participants.findIndex(p => p.id === targetId);
+    if (pointerIdx >= 0) {
+      const crosses = (a, b) => (a <= pointerIdx && b > pointerIdx) || (a > pointerIdx && b <= pointerIdx);
+      if (crosses(draggedIndex, targetIdx0)) {
+        return { patch: null, log: null }; // cross-pointer blocked
+      }
+    }
+  }
+  const [removedItem] = participants.splice(draggedIndex, 1);
+  const newTargetIndex = participants.findIndex(p => p.id === targetId);
+  participants.splice(newTargetIndex, 0, removedItem);
+  const turnUpdates = syncTurnOrder(participants); // 1-list: always mirror
+  return {
+    patch: { participants, ...turnUpdates },
+    log: {
+      message: `${removedItem.name} reordered before ${(participants.find(p => p.id === targetId) || {}).name || targetId}`,
+      undo: {
+        participants: encounter.participants || [],
+        turnOrderIds: encounter.turnOrderIds || [],
+        currentTurnParticipantId: encounter.currentTurnParticipantId ?? null,
+      },
+    },
+  };
+}
+
+// END_ENCOUNTER — verbatim from InitiativeControls.confirmEndEncounter
+function endEncounter(encounter) {
+  return {
+    patch: {
+      isStarted: false,
+      isPaused: false,
+      currentTurnParticipantId: null,
+      round: 0,
+      turnOrderIds: [],
+    },
+    log: {
+      message: `Combat ended: "${encounter.name}"`,
+      undo: {
+        isStarted: encounter.isStarted ?? false,
+        isPaused: encounter.isPaused ?? false,
+        round: encounter.round ?? 0,
+        currentTurnParticipantId: encounter.currentTurnParticipantId ?? null,
+        turnOrderIds: [...(encounter.turnOrderIds || [])],
+      },
+    },
+  };
+}
+
+// ----------------------------------------------------------------------------
+// Display lifecycle (activeDisplay/status doc). Pure patches, same shape as
+// App's inline storage.updateDoc(getPath.activeDisplay(), ...). Single source.
+// Callers persist patch to the activeDisplay/status doc.
+// ----------------------------------------------------------------------------
+
+// ACTIVATE_DISPLAY — start combat: point player display at this encounter.
+function activateDisplay({ campaignId, encounterId }) {
+  return { patch: { activeCampaignId: campaignId, activeEncounterId: encounterId } };
+}
+
+// CLEAR_DISPLAY — end combat: player display shows nothing.
+function clearDisplay() {
+  return { patch: { activeCampaignId: null, activeEncounterId: null } };
+}
+
+// TOGGLE_HIDE_PLAYER_HP — flip player-HP visibility on display.
+function toggleHidePlayerHp(currentValue) {
+  return { patch: { hidePlayerHp: !currentValue } };
+}
+
+module.exports = {
+  DEFAULT_MAX_HP,
+  DEFAULT_INIT_MOD,
+  MONSTER_DEFAULT_INIT_MOD,
+  generateId,
+  rollD20,
+  formatInitMod,
+  sortParticipantsByInitiative,
+  syncTurnOrder,
+  computeTurnOrderAfterRemoval,
+  makeParticipant,
+  buildCharacterParticipant,
+  buildMonsterParticipant,
+  startEncounter,
+  nextTurn,
+  togglePause,
+  addParticipant,
+  addParticipants,
+  updateParticipant,
+  removeParticipant,
+  toggleParticipantActive,
+  applyHpChange,
+  deathSave,
+  toggleCondition,
+  reorderParticipants,
+  endEncounter,
+  activateDisplay,
+  clearDisplay,
+  toggleHidePlayerHp,
+};

src/__mocks__/firebase/_mock-db.js

@@ -0,0 +1,91 @@
+// Mock in-memory Firestore for jest tests.
+// Reset via resetMockDb() in setupTests.js beforeEach.
+
+const state = {
+  docs: new Map(),        // path -> data
+  subscribers: new Map(), // path -> Set<cb>
+  counter: 0,
+  calls: [],              // recorded SDK calls
+};
+
+export const MOCK_DB = {
+  get(path) { return state.docs.has(path) ? clone(state.docs.get(path)) : null; },
+  set(path, data) {
+    state.docs.set(path, clone(data));
+    this._notify(path);
+  },
+  merge(path, patch) {
+    const cur = state.docs.has(path) ? state.docs.get(path) : {};
+    const next = { ...cur, ...clone(patch) };
+    state.docs.set(path, next);
+    this._notify(path);
+  },
+  delete(path) {
+    state.docs.delete(path);
+    this._notify(path);
+  },
+  collection(collPath) {
+    const out = [];
+    for (const [p, data] of state.docs) {
+      const parent = p.split('/').slice(0, -1).join('/');
+      if (parent === collPath) out.push({ id: p.split('/').pop(), data: clone(data) });
+    }
+    return out;
+  },
+  subscribe(path, cb) {
+    if (!state.subscribers.has(path)) state.subscribers.set(path, new Set());
+    state.subscribers.get(path).add(cb);
+    return () => state.subscribers.get(path)?.delete(cb);
+  },
+  _notify(path) {
+    // notify exact doc path subscribers (wrapped in act for test isolation).
+    // Set flag true around cb: testing-library asyncWrapper (waitFor) flips it
+    // false during poll, which makes raw react act() warn 'not configured'.
+    if (state.subscribers.has(path)) state.subscribers.get(path).forEach(cb => {
+      try {
+        const { act } = require('react');
+        const prev = globalThis.IS_REACT_ACT_ENVIRONMENT;
+        globalThis.IS_REACT_ACT_ENVIRONMENT = true;
+        act(() => cb());
+        globalThis.IS_REACT_ACT_ENVIRONMENT = prev;
+      } catch {
+        cb();
+      }
+    });
+    // notify parent collection subscribers
+    const parent = path.split('/').slice(0, -1).join('/');
+    if (parent && state.subscribers.has(parent)) state.subscribers.get(parent).forEach(cb => {
+      try {
+        const { act } = require('react');
+        const prev = globalThis.IS_REACT_ACT_ENVIRONMENT;
+        globalThis.IS_REACT_ACT_ENVIRONMENT = true;
+        act(() => cb());
+        globalThis.IS_REACT_ACT_ENVIRONMENT = prev;
+      } catch {
+        cb();
+      }
+    });
+  },
+  nextId() { state.counter += 1; return String(state.counter).padStart(3, '0'); },
+  _state: state,
+};
+
+export function recordCall(entry) {
+  state.calls.push({ ...entry, ts: Date.now() });
+}
+
+export function resetMockDb() {
+  state.docs.clear();
+  state.subscribers.clear();
+  state.calls.length = 0;
+  state.counter = 0;
+}
+
+export function getCalls() {
+  return [...state.calls];
+}
+
+function clone(v) {
+  if (v === null || v === undefined) return v;
+  return JSON.parse(JSON.stringify(v));
+}

src/__mocks__/firebase/app.js

@@ -0,0 +1,5 @@
+// jest manual mock: firebase/app
+const fakeApp = { name: '[fake-firebase-app]', options: {} };
+export function initializeApp(config) { return fakeApp; }
+export const getApp = () => fakeApp;
+export const getApps = () => [fakeApp];

src/__mocks__/firebase/auth.js

@@ -0,0 +1,11 @@
+// jest manual mock: firebase/auth
+const fakeUser = { uid: 'test-user-123', isAnonymous: true };
+const fakeAuth = { currentUser: fakeUser };
+
+export function getAuth() { return fakeAuth; }
+export function signInAnonymously(auth) { return Promise.resolve({ user: fakeUser }); }
+export function signInWithCustomToken(auth, token) { return Promise.resolve({ user: fakeUser }); }
+export function onAuthStateChanged(auth, cb) {
+  cb(fakeUser);
+  return () => {};
+}

src/__mocks__/firebase/firestore.js

@@ -0,0 +1,123 @@
+// jest manual mock: firebase/firestore
+// Records all calls so tests can assert path/payload/semantics.
+// Global __firestoreCalls reset per test (see setupTests.js).
+
+import { MOCK_DB, recordCall } from './_mock-db.js';
+
+const ref = (path) => ({ __ref: true, path, id: path.split('/').pop() });
+
+export function getFirestore() { return { __db: true }; }
+export function doc(db, path, extra) {
+  const p = extra ? `${path}/${extra}` : path;
+  return ref(p);
+}
+export function collection(db, path) { return ref(path); }
+export function query(refOrColl, ...constraints) { return { ref: refOrColl, constraints }; }
+export function orderBy(field, dir) { return { __type: 'orderBy', field, dir }; }
+export function limit(n) { return { __type: 'limit', n }; }
+
+// writes
+export async function setDoc(docRef, data, opts) {
+  recordCall({ fn: 'setDoc', path: docRef.path, data: clone(data), opts: opts || null });
+  if (opts && opts.merge) {
+    MOCK_DB.merge(docRef.path, clone(data));
+  } else {
+    MOCK_DB.set(docRef.path, clone(data));
+  }
+  return undefined;
+}
+export async function updateDoc(docRef, patch) {
+  recordCall({ fn: 'updateDoc', path: docRef.path, data: clone(patch) });
+  MOCK_DB.merge(docRef.path, clone(patch));
+  return undefined;
+}
+export async function deleteDoc(docRef) {
+  recordCall({ fn: 'deleteDoc', path: docRef.path });
+  MOCK_DB.delete(docRef.path);
+  return undefined;
+}
+export async function addDoc(collRef, data) {
+  const id = `auto_${MOCK_DB.nextId()}`;
+  const path = `${collRef.path}/${id}`;
+  recordCall({ fn: 'addDoc', path, data: clone(data) });
+  MOCK_DB.set(path, clone(data));
+  return { id, path };
+}
+export function writeBatch(db) {
+  const ops = [];
+  return {
+    set: (r, d) => ops.push({ op: 'set', path: r.path, data: clone(d) }),
+    update: (r, d) => ops.push({ op: 'update', path: r.path, data: clone(d) }),
+    delete: (r) => ops.push({ op: 'delete', path: r.path }),
+    commit: async () => {
+      ops.forEach(o => {
+        recordCall({ fn: `batch.${o.op}`, path: o.path, data: o.data });
+        if (o.op === 'set') MOCK_DB.set(o.path, o.data);
+        else if (o.op === 'update') MOCK_DB.merge(o.path, o.data);
+        else if (o.op === 'delete') MOCK_DB.delete(o.path);
+      });
+    },
+  };
+}
+
+// reads (return from in-memory mock DB)
+export async function getDoc(docRef) {
+  const data = MOCK_DB.get(docRef.path);
+  return { exists: () => data !== null, id: docRef.id, data: () => data };
+}
+export async function getDocs(collRefOrQuery) {
+  const collPath = collRefOrQuery.ref ? collRefOrQuery.ref.path : collRefOrQuery.path;
+  const docs = MOCK_DB.collection(collPath);
+  return { docs: docs.map(d => ({ id: d.id, data: () => d.data, ref: { path: `${collPath}/${d.id}` } })) };
+}
+
+// realtime — emit from mock DB, capture unsub
+export function onSnapshot(refOrQuery, onSuccess, onError) {
+  const path = refOrQuery.path || (refOrQuery.ref && refOrQuery.ref.path);
+  const constraints = refOrQuery.constraints || [];
+  // fire immediately with current state
+  const emit = () => {
+    if (refOrQuery.__ref && refOrQuery.path && path.split('/').length % 2 === 0) {
+      const data = MOCK_DB.get(path);
+      onSuccess({
+        exists: () => data !== null,
+        id: path.split('/').pop(),
+        data: () => data,
+      });
+    } else {
+      let docs = MOCK_DB.collection(path);
+      docs = applyConstraints(docs, constraints);
+      onSuccess({ docs: docs.map(d => ({ id: d.id, data: () => d.data })) });
+    }
+  };
+  emit();
+  // register for future changes on this path
+  const unsub = MOCK_DB.subscribe(path, emit);
+  return unsub;
+}
+
+// Apply Firestore-style query constraints (orderBy desc/asc, limit) to mock docs.
+// Mirrors real SDK semantics enough for contract tests. Only orderBy + limit
+// supported (App's LOG_QUERY uses exactly these).
+function applyConstraints(docs, constraints) {
+  let out = [...docs];
+  for (const c of constraints) {
+    if (c.__type === 'orderBy') {
+      out.sort((a, b) => {
+        const av = a.data[c.field];
+        const bv = b.data[c.field];
+        if (av === bv) return 0;
+        const cmp = av > bv ? 1 : -1;
+        return c.dir === 'desc' ? -cmp : cmp;
+      });
+    } else if (c.__type === 'limit') {
+      out = out.slice(0, c.n);
+    }
+  }
+  return out;
+}
+
+function clone(v) {
+  if (v === null || v === undefined) return v;
+  return JSON.parse(JSON.stringify(v));
+}

src/index.css

@@ -7,14 +7,9 @@
 
 body {
   margin: 0;
-  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
-    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
-    sans-serif;
+  font-family: 'Alegreya Sans', system-ui, sans-serif;
   -webkit-font-smoothing: antialiased;
   -moz-osx-font-smoothing: grayscale;
-  /* background-color: #1A202C; /* Tailwind Slate 900 */
-  /* color: #E2E8F0;       /* Tailwind Slate 200 */
-  /* These will likely be overridden by the App component's Tailwind classes */
 }
 
 code {

src/setupTests.js

@@ -0,0 +1,47 @@
+// jest setup: RTL jest-dom + mock DB reset per test.
+import '@testing-library/jest-dom';
+import { resetMockDb } from './__mocks__/firebase/_mock-db';
+
+// RTL v14: tell React this is an act environment. Without it every
+// async update warns "current testing environment is not configured to
+// support act(...)". RTL reads getGlobalThis(), so set on globalThis.
+// Must be set before any component renders.
+globalThis.IS_REACT_ACT_ENVIRONMENT = true;
+
+// Test timeout guard. CRA blocks `testTimeout` in package.json jest config
+// (not in allowlist). Set via jest global here instead. Fails fast on hang.
+jest.setTimeout(10000);
+
+// WARNING = FAILURE. Fail test on any console.error/warn (React act warnings,
+// deprecations, prop errors). App code's own error logs allowed only inside
+// try/catch failure paths — those tests should assert the error was handled,
+// not silently log it. Override the spies to throw.
+const originalError = console.error;
+const originalWarn = console.warn;
+console.error = (...args) => {
+  originalError(...args);
+  throw new Error(`console.error in test: ${args.map(String).join(' ').slice(0, 500)}`);
+};
+console.warn = (...args) => {
+  originalWarn(...args);
+  throw new Error(`console.warn in test: ${args.map(String).join(' ').slice(0, 500)}`);
+};
+
+// polyfill crypto.randomUUID for jsdom (used by generateId in App.js).
+if (!global.crypto) global.crypto = {};
+if (!global.crypto.randomUUID) {
+  global.crypto.randomUUID = () => 'test-uuid-' + Math.random().toString(36).slice(2, 10);
+}
+
+// Stub Firebase env vars so initializeFirebase() succeeds under test.
+// Real SDK calls are mocked via __mocks__/firebase/*.
+process.env.REACT_APP_FIREBASE_API_KEY = 'test-api-key';
+process.env.REACT_APP_FIREBASE_AUTH_DOMAIN = 'test.firebaseapp.com';
+process.env.REACT_APP_FIREBASE_PROJECT_ID = 'test-project';
+process.env.REACT_APP_FIREBASE_STORAGE_BUCKET = 'test.appspot.com';
+process.env.REACT_APP_FIREBASE_MESSAGING_SENDER_ID = '1234567890';
+process.env.REACT_APP_FIREBASE_APP_ID = '1:1234567890:web:abcdef';
+
+beforeEach(() => {
+  resetMockDb();
+});

src/storage/contract.js

@@ -0,0 +1,283 @@
+// Storage interface contract.
+// This is the SPEC. Runs against any storage impl (memory, ws, firebase).
+// TDD: written first (RED), impl built to satisfy (GREEN).
+//
+// Usage:
+//   const { runStorageContract } = require('./contract.test');
+//   runStorageContract('memory', () => createMemoryStorage());
+
+'use strict';
+
+// Each impl factory returns a fresh storage instance (async-creatable is fine).
+// Interface every impl MUST provide:
+//   getDoc(path)              -> Promise<obj|null>
+//   setDoc(path, data)        -> Promise<void>           (replace)
+//   updateDoc(path, patch)    -> Promise<void>           (shallow merge)
+//   deleteDoc(path)           -> Promise<void>
+//   addDoc(collectionPath, data) -> Promise<{id, path}>  (auto-gen id)
+//   getCollection(path)       -> Promise<arr>            (immediate child docs)
+//   batchWrite(ops)           -> Promise<void>           ops: [{type, path, data?}]
+//   subscribeDoc(path, cb)    -> unsubscribe fn          cb(doc|null)
+//   subscribeCollection(path, cb) -> unsubscribe fn      cb(arr)
+
+function runStorageContract(name, factory) {
+  describe(`storage contract: ${name}`, () => {
+    let storage;
+    beforeEach(async () => { storage = await factory(); });
+    afterEach(async () => { if (storage && storage.dispose) await storage.dispose(); });
+
+    describe('getDoc / setDoc', () => {
+      test('setDoc then getDoc returns the doc (with id)', async () => {
+        await storage.setDoc('campaigns/a', { name: 'Alpha' });
+        const doc = await storage.getDoc('campaigns/a');
+        expect(doc).toEqual({ id: 'a', name: 'Alpha' });
+      });
+
+      test('getDoc on missing path returns null', async () => {
+        const doc = await storage.getDoc('campaigns/missing');
+        expect(doc).toBeNull();
+      });
+
+      test('setDoc overwrites entirely (not merge)', async () => {
+        await storage.setDoc('campaigns/a', { name: 'Alpha', players: [] });
+        await storage.setDoc('campaigns/a', { name: 'Beta' });
+        const doc = await storage.getDoc('campaigns/a');
+        expect(doc).toEqual({ id: 'a', name: 'Beta' });
+      });
+
+      // main L1624: setDoc(path, data, {merge:true}) — merge flag.
+      test('setDoc with {merge:true} merges into existing doc', async () => {
+        await storage.setDoc('campaigns/a', { name: 'Alpha', players: [] });
+        await storage.setDoc('campaigns/a', { players: [1] }, { merge: true });
+        const doc = await storage.getDoc('campaigns/a');
+        expect(doc).toEqual({ id: 'a', name: 'Alpha', players: [1] });
+      });
+    });
+
+    describe('updateDoc (shallow merge)', () => {
+      test('merges patch into existing doc', async () => {
+        await storage.setDoc('campaigns/a', { name: 'Alpha', players: [1] });
+        await storage.updateDoc('campaigns/a', { players: [1, 2] });
+        const doc = await storage.getDoc('campaigns/a');
+        expect(doc).toEqual({ id: 'a', name: 'Alpha', players: [1, 2] });
+      });
+
+      test('updateDoc on missing doc creates it', async () => {
+        await storage.updateDoc('campaigns/a', { name: 'Alpha' });
+        const doc = await storage.getDoc('campaigns/a');
+        expect(doc).toEqual({ id: 'a', name: 'Alpha' });
+      });
+    });
+
+    describe('deleteDoc', () => {
+      test('removes doc', async () => {
+        await storage.setDoc('campaigns/a', { name: 'Alpha' });
+        await storage.deleteDoc('campaigns/a');
+        expect(await storage.getDoc('campaigns/a')).toBeNull();
+      });
+
+      test('delete missing doc is no-op (no throw)', async () => {
+        await expect(storage.deleteDoc('campaigns/none')).resolves.toBeUndefined();
+      });
+    });
+
+    describe('addDoc', () => {
+      test('auto-generates id and stores doc at collection/id', async () => {
+        const { id, path } = await storage.addDoc('campaigns/a/encounters', { name: 'E1' });
+        expect(id).toBeTruthy();
+        expect(path).toBe(`campaigns/a/encounters/${id}`);
+        const doc = await storage.getDoc(path);
+        expect(doc).toEqual({ id, name: 'E1' });
+      });
+
+      test('two addDocs produce distinct ids', async () => {
+        const r1 = await storage.addDoc('logs', { m: 'one' });
+        const r2 = await storage.addDoc('logs', { m: 'two' });
+        expect(r1.id).not.toBe(r2.id);
+      });
+    });
+
+    describe('firebase-prefixed path identity', () => {
+      // App passes firebase-prefixed paths (artifacts/{APP_ID}/public/data/...).
+      // main prod truth: ALWAYS prefixed. Write+read same prefixed round-trips.
+      // Cross bare<->prefixed lookup is NOT required by main (App never does it).
+      // Kept as same-prefix roundtrip only — matches prod.
+      const PREFIX = 'artifacts/test-app/public/data';
+
+      test('setDoc prefixed then getDoc same prefixed path returns it (id)', async () => {
+        await storage.setDoc(`${PREFIX}/campaigns/c2`, { name: 'P2' });
+        const doc = await storage.getDoc(`${PREFIX}/campaigns/c2`);
+        expect(doc).toEqual({ id: 'c2', name: 'P2' });
+      });
+    });
+
+    describe('getCollection', () => {
+      test('returns immediate child docs only (not nested)', async () => {
+        await storage.setDoc('campaigns/a', { name: 'A' });
+        await storage.setDoc('campaigns/b', { name: 'B' });
+        await storage.setDoc('campaigns/a/encounters/e1', { name: 'E1' });
+        const docs = await storage.getCollection('campaigns');
+        expect(docs).toHaveLength(2);
+        const names = docs.map(d => d.name).sort();
+        expect(names).toEqual(['A', 'B']);
+      });
+
+      test('empty collection returns []', async () => {
+        const docs = await storage.getCollection('campaigns');
+        expect(docs).toEqual([]);
+      });
+
+      test('subcollection returns only its direct children', async () => {
+        await storage.setDoc('campaigns/a/encounters/e1', { name: 'E1' });
+        await storage.setDoc('campaigns/a/encounters/e2', { name: 'E2' });
+        await storage.setDoc('campaigns/a/encounters/e1/participants/p1', { name: 'P1' });
+        const docs = await storage.getCollection('campaigns/a/encounters');
+        expect(docs).toHaveLength(2);
+      });
+    });
+
+    describe('batchWrite', () => {
+      test('applies multiple deletes atomically', async () => {
+        await storage.setDoc('campaigns/a', { name: 'A' });
+        await storage.setDoc('campaigns/b', { name: 'B' });
+        await storage.batchWrite([
+          { type: 'delete', path: 'campaigns/a' },
+          { type: 'delete', path: 'campaigns/b' },
+        ]);
+        expect(await storage.getDoc('campaigns/a')).toBeNull();
+        expect(await storage.getDoc('campaigns/b')).toBeNull();
+      });
+
+      test('applies set + delete mixed', async () => {
+        await storage.setDoc('campaigns/a', { name: 'A' });
+        await storage.batchWrite([
+          { type: 'set', path: 'campaigns/b', data: { name: 'B' } },
+          { type: 'delete', path: 'campaigns/a' },
+        ]);
+        expect(await storage.getDoc('campaigns/a')).toBeNull();
+        expect(await storage.getDoc('campaigns/b')).toEqual({ id: 'b', name: 'B' });
+      });
+
+      // set-only batch (not used in main currently, but interface allows).
+      test('applies set-only batch', async () => {
+        await storage.batchWrite([
+          { type: 'set', path: 'campaigns/a', data: { name: 'A' } },
+          { type: 'set', path: 'campaigns/b', data: { name: 'B' } },
+        ]);
+        expect(await storage.getDoc('campaigns/a')).toEqual({ id: 'a', name: 'A' });
+        expect(await storage.getDoc('campaigns/b')).toEqual({ id: 'b', name: 'B' });
+      });
+
+      // update-only batch (interface allows).
+      test('applies update-only batch', async () => {
+        await storage.setDoc('campaigns/a', { name: 'A', hp: 10 });
+        await storage.setDoc('campaigns/b', { name: 'B', hp: 5 });
+        await storage.batchWrite([
+          { type: 'update', path: 'campaigns/a', data: { hp: 8 } },
+          { type: 'update', path: 'campaigns/b', data: { hp: 2 } },
+        ]);
+        expect(await storage.getDoc('campaigns/a')).toEqual({ id: 'a', name: 'A', hp: 8 });
+        expect(await storage.getDoc('campaigns/b')).toEqual({ id: 'b', name: 'B', hp: 2 });
+      });
+    });
+
+    describe('subscribeDoc', () => {
+      test('fires cb immediately with current value', async () => {
+        await storage.setDoc('campaigns/a', { name: 'Alpha' });
+        const calls = [];
+        storage.subscribeDoc('campaigns/a', (doc) => calls.push(doc));
+        await flush();
+        expect(calls).toHaveLength(1);
+        expect(calls[0]).toEqual({ id: 'a', name: 'Alpha' });
+      });
+
+      test('fires cb on subsequent change', async () => {
+        const calls = [];
+        storage.subscribeDoc('campaigns/a', (doc) => calls.push(doc));
+        await flush();
+        await storage.setDoc('campaigns/a', { name: 'Alpha' });
+        await flush();
+        const last = calls[calls.length - 1];
+        expect(last).toEqual({ id: 'a', name: 'Alpha' });
+      });
+
+      test('unsubscribe stops callbacks', async () => {
+        const calls = [];
+        const unsub = storage.subscribeDoc('campaigns/a', (doc) => calls.push(doc));
+        await flush();
+        unsub();
+        await storage.setDoc('campaigns/a', { name: 'X' });
+        await flush();
+        expect(calls.filter(Boolean)).toHaveLength(0);
+      });
+    });
+
+    describe('subscribeCollection', () => {
+      test('fires cb with current docs', async () => {
+        await storage.setDoc('campaigns/a', { name: 'A' });
+        const calls = [];
+        storage.subscribeCollection('campaigns', (docs) => calls.push(docs));
+        await flush();
+        expect(calls).toHaveLength(1);
+        expect(calls[0]).toHaveLength(1);
+      });
+
+      test('fires on add to collection', async () => {
+        const calls = [];
+        storage.subscribeCollection('campaigns', (docs) => calls.push(docs));
+        await flush();
+        await storage.setDoc('campaigns/a', { name: 'A' });
+        await flush();
+        const last = calls[calls.length - 1];
+        expect(last).toHaveLength(1);
+      });
+    });
+
+    // queryConstraints: orderBy + limit. App's combat log uses
+    // [orderBy('timestamp','desc'), limit(500)] — newest 500 entries.
+    // Adapter MUST honor these. Constraint shape = neutral {__type} objects
+    // (what firebase mock produces; what App passes via shared builders).
+    describe('subscribeCollection queryConstraints', () => {
+      const orderByC = (field, dir) => ({ __type: 'orderBy', field, dir });
+      const limitC = (n) => ({ __type: 'limit', n });
+
+      beforeEach(async () => {
+        // seed 5 log docs, timestamps out of order
+        await storage.setDoc('logs/l1', { msg: 'one', timestamp: 1 });
+        await storage.setDoc('logs/l2', { msg: 'two', timestamp: 3 });
+        await storage.setDoc('logs/l3', { msg: 'three', timestamp: 5 });
+        await storage.setDoc('logs/l4', { msg: 'four', timestamp: 2 });
+        await storage.setDoc('logs/l5', { msg: 'five', timestamp: 4 });
+      });
+
+      test('orderBy desc sorts newest-first', async () => {
+        const result = await new Promise((resolve) => {
+          storage.subscribeCollection('logs', resolve, [orderByC('timestamp', 'desc')]);
+        });
+        expect(result.map(d => d.msg)).toEqual(['three', 'five', 'two', 'four', 'one']);
+      });
+
+      test('limit returns only first N after ordering', async () => {
+        const result = await new Promise((resolve) => {
+          storage.subscribeCollection('logs', resolve, [orderByC('timestamp', 'desc'), limitC(2)]);
+        });
+        expect(result.map(d => d.msg)).toEqual(['three', 'five']);
+      });
+
+      test('no constraints returns all (insertion/id order)', async () => {
+        const result = await new Promise((resolve) => {
+          storage.subscribeCollection('logs', resolve, []);
+        });
+        expect(result).toHaveLength(5);
+      });
+    });
+  });
+}
+
+// flush so async subscribers settle. WS roundtrip needs real delay (network),
+// memory fires near-instant. 50ms covers localhost WS comfortably.
+function flush() {
+  return new Promise((resolve) => setTimeout(resolve, 50));
+}
+
+module.exports = { runStorageContract, flush };

src/storage/firebase.js

@@ -0,0 +1,160 @@
+// firebase.js — storage adapter wrapping Firebase SDK. Default impl (upstream-unchanged).
+// Matches interface of memory.js / ws.js so App.js calls stay identical.
+//
+// App.js imports SDK via this module (doc, setDoc, etc re-exported) for both
+// the adapter (createFirebaseStorage) and direct SDK calls. ONE import path.
+
+'use strict';
+
+import { initializeApp } from 'firebase/app';
+import { getAuth, signInAnonymously, onAuthStateChanged, signInWithCustomToken } from 'firebase/auth';
+import {
+  getFirestore, doc, setDoc, getDoc as getDocReal, getDocs as getDocsReal, addDoc, collection,
+  onSnapshot, updateDoc, deleteDoc, query, orderBy, limit, writeBatch, serverTimestamp,
+} from 'firebase/firestore';
+
+// Adapter call recorder (instrumentation, no behavior change).
+// Tests assert adapter.subscribeDoc called (catches raw-SDK bypass like DisplayView).
+const ADAPTER_CALLS = [];
+function recordAdapterCall(entry) { ADAPTER_CALLS.push({ ...entry, ts: Date.now() }); }
+export function getAdapterCalls() { return [...ADAPTER_CALLS]; }
+export function resetAdapterCalls() { ADAPTER_CALLS.length = 0; }
+
+// Path helpers mirror App.js getPath object.
+const APP_ID = process.env.REACT_APP_TRACKER_APP_ID || 'ttrpg-initiative-tracker-default';
+const PUBLIC_DATA_PATH = `artifacts/${APP_ID}/public/data`;
+
+export const getPath = {
+  campaigns: () => `${PUBLIC_DATA_PATH}/campaigns`,
+  campaign: (id) => `${PUBLIC_DATA_PATH}/campaigns/${id}`,
+  encounters: (campaignId) => `${PUBLIC_DATA_PATH}/campaigns/${campaignId}/encounters`,
+  encounter: (campaignId, encounterId) => `${PUBLIC_DATA_PATH}/campaigns/${campaignId}/encounters/${encounterId}`,
+  activeDisplay: () => `${PUBLIC_DATA_PATH}/activeDisplay/status`,
+  logs: () => `${PUBLIC_DATA_PATH}/logs`
+};
+
+let firebaseApp = null;
+let dbInstance = null;
+let authInstance = null;
+
+export function initFirebase() {
+  const config = {
+    apiKey: process.env.REACT_APP_FIREBASE_API_KEY,
+    authDomain: process.env.REACT_APP_FIREBASE_AUTH_DOMAIN,
+    projectId: process.env.REACT_APP_FIREBASE_PROJECT_ID,
+    storageBucket: process.env.REACT_APP_FIREBASE_STORAGE_BUCKET,
+    messagingSenderId: process.env.REACT_APP_FIREBASE_MESSAGING_SENDER_ID,
+    appId: process.env.REACT_APP_FIREBASE_APP_ID
+  };
+  const requiredKeys = ['apiKey', 'authDomain', 'projectId', 'appId'];
+  const missing = requiredKeys.filter(k => !config[k]);
+  if (missing.length > 0) {
+    console.error(`CRITICAL: Missing Firebase config: ${missing.join(', ')}`);
+    return false;
+  }
+  try {
+    firebaseApp = initializeApp(config);
+    dbInstance = getFirestore(firebaseApp);
+    authInstance = getAuth(firebaseApp);
+    return true;
+  } catch (err) {
+    console.error('Firebase init failed:', err);
+    return false;
+  }
+}
+
+export function getDb() { return dbInstance; }
+export function getAuthInstance() { return authInstance; }
+
+// ============================================================================
+// STORAGE ADAPTER
+// ============================================================================
+// Wraps SDK in the storage interface (getDoc/setDoc/etc).
+// App.js can now import { storage } and call storage.setDoc(path, data).
+// Hooks (useFirestoreDocument etc) still use SDK directly for now.
+
+export function createFirebaseStorage() {
+  const db = dbInstance;
+  if (!db) throw new Error('Firestore not initialized. Call initFirebase() first.');
+
+  return {
+    async getDoc(path) {
+      const snap = await getDocReal(doc(db, path));
+      return snap.exists() ? { id: snap.id, ...snap.data() } : null;
+    },
+
+    async setDoc(path, data, opts = {}) {
+      recordAdapterCall({ fn: 'setDoc', path, data, opts });
+      await setDoc(doc(db, path), data, opts.merge ? { merge: true } : undefined);
+    },
+
+    async updateDoc(path, patch) {
+      recordAdapterCall({ fn: 'updateDoc', path, patch });
+      await updateDoc(doc(db, path), patch);
+    },
+
+    async deleteDoc(path) {
+      await deleteDoc(doc(db, path));
+    },
+
+    async addDoc(collectionPath, data) {
+      const ref = await addDoc(collection(db, collectionPath), data);
+      return { id: ref.id, path: `${collectionPath}/${ref.id}` };
+    },
+
+    async getCollection(collectionPath) {
+      const snapshot = await getDocsReal(collection(db, collectionPath));
+      return snapshot.docs.map(d => ({ id: d.id, ...d.data() }));
+    },
+
+    async batchWrite(ops) {
+      const batch = writeBatch(db);
+      for (const op of ops) {
+        if (op.type === 'set') batch.set(doc(db, op.path), op.data);
+        else if (op.type === 'delete') batch.delete(doc(db, op.path));
+        else if (op.type === 'update') batch.update(doc(db, op.path), op.data);
+      }
+      await batch.commit();
+    },
+
+    // Subscribe = onSnapshot. cb fires immediately + on change. Returns unsubscribe.
+    subscribeDoc(path, cb, errCb) {
+      recordAdapterCall({ fn: 'subscribeDoc', path });
+      return onSnapshot(doc(db, path), (snap) => {
+        cb(snap.exists() ? { id: snap.id, ...snap.data() } : null);
+      }, (err) => {
+        console.error(`subscribeDoc ${path}:`, err);
+        if (typeof errCb === 'function') errCb(err);
+      });
+    },
+
+    subscribeCollection(collectionPath, cb, queryConstraints = [], errCb) {
+      recordAdapterCall({ fn: 'subscribeCollection', path: collectionPath });
+      // queryConstraints = neutral {__type} builders (from index.js).
+      // Translate to SDK orderBy/limit.
+      const sdkConstraints = queryConstraints.map(c => {
+        if (c.__type === 'orderBy') return orderBy(c.field, c.dir);
+        if (c.__type === 'limit') return limit(c.n);
+        return c; // pass-through (forward compat)
+      });
+      const q = sdkConstraints.length > 0
+        ? query(collection(db, collectionPath), ...sdkConstraints)
+        : collection(db, collectionPath);
+      return onSnapshot(q, (snap) => {
+        cb(snap.docs.map(d => ({ id: d.id, ...d.data() })));
+      }, (err) => {
+        console.error(`subscribeCollection ${collectionPath}:`, err);
+        if (typeof errCb === 'function') errCb(err);
+      });
+    },
+
+    dispose() { /* SDK managed; no-op */ },
+  };
+}
+
+// Re-export SDK pieces App.js uses directly (until full refactor).
+// orderBy/limit NOT re-exported: App uses neutral builders from index.js.
+export {
+  doc, setDoc, updateDoc, deleteDoc, addDoc, collection, onSnapshot,
+  query, writeBatch,
+};

src/storage/index.js

@@ -0,0 +1,54 @@
+// src/storage/index.js — storage factory + SDK re-exports.
+// STORAGE=firebase (default): adapter wraps SDK. STORAGE=server: backend.
+// orderBy/limit below = NEUTRAL builders (not SDK passthrough).
+// App.js imports getStorage() for subscribe; still imports SDK pieces for writes (per-group refactor pending).
+
+import { initializeApp } from 'firebase/app';
+import {
+  getAuth, signInAnonymously, onAuthStateChanged, signInWithCustomToken,
+} from 'firebase/auth';
+import {
+  getFirestore, doc, setDoc, getDoc, getDocs, addDoc, collection,
+  onSnapshot, updateDoc, deleteDoc, query, writeBatch,
+} from 'firebase/firestore';
+import { initFirebase, createFirebaseStorage } from './firebase';
+import { createServerStorage } from './server';
+
+let storageInstance = null;
+
+// Returns adapter instance implementing interface (getDoc/setDoc/subscribeDoc/etc).
+export function getStorage() {
+  if (storageInstance) return storageInstance;
+  const mode = process.env.REACT_APP_STORAGE || 'firebase';
+  if (mode === 'firebase') {
+    const ok = initFirebase();
+    if (!ok) throw new Error('Firebase config missing. Check REACT_APP_FIREBASE_* env.');
+    storageInstance = createFirebaseStorage();
+  } else if (mode === 'server') {
+    storageInstance = createServerStorage({
+      baseUrl: process.env.REACT_APP_BACKEND_URL || '',
+      realtimeUrl: process.env.REACT_APP_BACKEND_REALTIME_URL || '',
+    });
+  } else {
+    throw new Error(`Unknown REACT_APP_STORAGE mode: ${mode}. Use 'firebase' or 'server'.`);
+  }
+  return storageInstance;
+}
+
+export function getStorageMode() {
+  return process.env.REACT_APP_STORAGE || 'firebase';
+}
+
+// Neutral query-constraint builders. App builds constraints with these (not
+// raw SDK), so both adapters read the same shape. firebase adapter translates
+// neutral -> SDK; server adapter applies client-side. Combat log uses these:
+//   [orderBy('timestamp','desc'), limit(500)]
+export function orderBy(field, dir) { return { __type: 'orderBy', field, dir }; }
+export function limit(n) { return { __type: 'limit', n }; }
+
+export {
+  initializeApp,
+  getAuth, signInAnonymously, onAuthStateChanged, signInWithCustomToken,
+  getFirestore, doc, setDoc, getDoc, getDocs, addDoc, collection,
+  onSnapshot, updateDoc, deleteDoc, query, writeBatch,
+};

src/storage/server.js

@@ -0,0 +1,289 @@
+// ws.js — thin storage adapter over generic KV backend (HTTP + WebSocket).
+// Passthrough: no shape translation. Backend = firebase mirror.
+// Implements same interface as memory.js. Tested by storage contract vs running server.
+
+'use strict';
+
+// Native browser WebSocket if present, else ws pkg (Node/jest).
+// Lazy load ws pkg so CRA prod build (ESM) doesn't choke on require().
+let WebSocketImpl;
+if (typeof WebSocket !== 'undefined') {
+  WebSocketImpl = WebSocket;
+}
+
+function createServerStorage({ baseUrl, realtimeUrl } = {}) {
+  // Same-origin by default: empty baseUrl = relative fetch (Caddy/proxy).
+  // Fallback to localhost for bare `npm start` dev without proxy.
+  const API = (baseUrl || (typeof window !== 'undefined' && window.location ? '' : 'http://127.0.0.1:4001')).replace(/\/$/, '');
+  let WS;
+  if (realtimeUrl) {
+    WS = realtimeUrl;
+  } else if (typeof window !== 'undefined' && window.location) {
+    // derive from current origin (http→ws, https→wss), same host/port.
+    const proto = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
+    WS = `${proto}//${window.location.host}/ws`;
+  } else {
+    WS = 'ws://127.0.0.1:4001/ws';
+  }
+
+  // App passes firebase-prefixed paths: artifacts/{APP_ID}/public/data/campaigns/...
+  // Backend uses canonical paths. Strip prefix.
+  function norm(p) {
+    if (!p) return p;
+    return p.replace(/^[\s\S]*\/public\/data\//, '');
+  }
+
+  // Inject id (last path segment) into doc — matches main firebase truth:
+  //   { id: docSnap.id, ...snap.data() }
+  // Backend stores docs WITHOUT id; client adds it so all adapters share shape.
+  function withId(rawPath, data) {
+    if (data === null || data === undefined) return data;
+    const id = norm(rawPath).split('/').pop();
+    return { id, ...data };
+  }
+
+  // Apply neutral {__type} query constraints client-side. Backend returns all
+  // docs; adapter sorts/limits. Mirrors firebase mock applyConstraints.
+  function applyConstraints(docs, constraints) {
+    let out = [...docs];
+    for (const c of constraints || []) {
+      if (!c || !c.__type) continue;
+      if (c.__type === 'orderBy') {
+        out.sort((a, b) => {
+          const av = a[c.field];
+          const bv = b[c.field];
+          if (av === bv) return 0;
+          const cmp = av > bv ? 1 : -1;
+          return c.dir === 'desc' ? -cmp : cmp;
+        });
+      } else if (c.__type === 'limit') {
+        out = out.slice(0, c.n);
+      }
+    }
+    return out;
+  }
+
+  const docSubs = new Map();      // path -> Set<cb>
+  const collSubs = new Map();     // collPath -> Set<cb>
+  const collConstraints = new Map(); // collPath -> constraints[] (per collection)
+  let ws = null;
+  let wsReady = null;
+
+  let disposed = false;
+  let reconnectTimer = null;
+  let everConnected = false;
+  const RECONNECT_DELAY = 500;
+
+  function ensureWs() {
+    if (wsReady) return wsReady;
+    wsReady = new Promise((resolve, reject) => {
+      (async () => {
+        // Node/jest only: load ws pkg via dynamic import. Browser uses global
+        // WebSocket. Avoids require() in CRA prod ESM bundle (webpack crash).
+        let WsClass = WebSocketImpl;
+        if (!WsClass) {
+          const wsPkg = await import('ws');
+          WsClass = wsPkg.WebSocket;
+        }
+        ws = new WsClass(WS);
+      const onOpen = () => {
+        const isReconnect = everConnected;
+        everConnected = true;
+        // resubscribe all existing subscribers after (re)connect
+        for (const p of docSubs.keys()) {
+          ws.send(JSON.stringify({ type: 'subscribe', kind: 'doc', path: p }));
+        }
+        for (const p of collSubs.keys()) {
+          ws.send(JSON.stringify({ type: 'subscribe', kind: 'collection', path: p }));
+        }
+        // On RECONNECT only: re-fetch current values — catches writes that
+        // happened while disconnected (broadcast missed). Skip on first connect
+        // (initial REST fetch in subscribeDoc/subscribeCollection already did).
+        if (isReconnect) {
+          for (const [p, cbs] of docSubs) {
+            storage.getDoc(p).then(doc => { cbs.forEach(cb => cb(doc)); }).catch(() => {});
+          }
+          for (const [p, cbs] of collSubs) {
+            storage.getCollection(p).then(docs => { cbs.forEach(cb => cb(docs)); }).catch(() => {});
+          }
+        }
+        resolve(ws);
+      };
+      const onError = (err) => { wsReady = null; reject(err instanceof Event ? new Error('ws error') : err); };
+      const onClose = () => {
+        wsReady = null;
+        ws = null;
+        if (disposed) return;
+        // auto-reconnect (BUG-8): try again after delay. ensureWs() re-arms.
+        if (reconnectTimer) clearTimeout(reconnectTimer);
+        reconnectTimer = setTimeout(() => {
+          reconnectTimer = null;
+          if (!disposed) ensureWs().catch(() => {});
+        }, RECONNECT_DELAY);
+        if (reconnectTimer && typeof reconnectTimer.unref === 'function') reconnectTimer.unref();
+      };
+      const onMessage = (ev) => {
+        const raw = typeof ev === 'string' ? ev : (ev.data !== undefined ? ev.data : ev);
+        let msg; try { msg = JSON.parse(typeof raw === 'string' ? raw : raw.toString()); } catch { return; }
+        handleMessage(msg);
+      };
+      ws.onopen = onOpen;
+      ws.onerror = onError;
+      ws.onclose = onClose;
+      ws.onmessage = onMessage;
+      if (typeof ws.addEventListener === 'function') {
+        ws.addEventListener('open', onOpen);
+        ws.addEventListener('error', onError);
+        ws.addEventListener('close', onClose);
+        ws.addEventListener('message', onMessage);
+      }
+      })();
+    });
+    return wsReady;
+  }
+
+  // Backend pushes change notices keyed by path. Re-fetch affected subscribers.
+  async function handleMessage(msg) {
+    if (msg.type !== 'change' || !msg.change) return;
+    const c = msg.change;
+    // doc subscriber at exact changed path
+    const docCbs = docSubs.get(c.path);
+    if (docCbs) {
+      const doc = await storage.getDoc(c.path);
+      docCbs.forEach(cb => cb(doc));
+    }
+    // collection subscribers at parent path (apply their stored constraints)
+    if (c.parent) {
+      const collCbs = collSubs.get(c.parent);
+      if (collCbs) {
+        const constraints = collConstraints.get(c.parent) || [];
+        const docs = applyConstraints(await storage.getCollection(c.parent), constraints);
+        collCbs.forEach(cb => cb(docs));
+      }
+    }
+  }
+
+  async function api(method, path, query, body) {
+    let url = `${API}${path}`;
+    if (query) {
+      const qs = new URLSearchParams(query).toString();
+      url += `?${qs}`;
+    }
+    const res = await fetch(url, {
+      method,
+      headers: body ? { 'Content-Type': 'application/json' } : undefined,
+      body: body ? JSON.stringify(body) : undefined,
+    });
+    if (!res.ok) {
+      const t = await res.text().catch(() => '');
+      throw new Error(`API ${method} ${path} ${res.status}: ${t}`);
+    }
+    const text = await res.text();
+    return text ? JSON.parse(text) : null;
+  }
+
+  const storage = {
+    async getDoc(rawPath) {
+      const p = norm(rawPath);
+      const res = await api('GET', '/api/doc', { path: p });
+      const data = res && res.data !== undefined ? res.data : null;
+      return withId(rawPath, data);
+    },
+
+    async setDoc(rawPath, data, opts = {}) {
+      const p = norm(rawPath);
+      // merge flag -> PATCH (shallow merge, create-on-miss). Matches firebase
+      // setDoc(path, data, {merge:true}) semantics.
+      if (opts.merge) {
+        await api('PATCH', '/api/doc', null, { path: p, patch: data });
+      } else {
+        await api('PUT', '/api/doc', null, { path: p, data });
+      }
+    },
+
+    async updateDoc(rawPath, patch) {
+      const p = norm(rawPath);
+      await api('PATCH', '/api/doc', null, { path: p, patch });
+    },
+
+    async deleteDoc(rawPath) {
+      const p = norm(rawPath);
+      await api('DELETE', '/api/doc', { path: p });
+    },
+
+    async addDoc(rawCollPath, data) {
+      const p = norm(rawCollPath);
+      const res = await api('POST', '/api/collection', null, { path: p, data });
+      return { id: res.id, path: res.path };
+    },
+
+    async getCollection(rawCollPath) {
+      const p = norm(rawCollPath);
+      const docs = await api('GET', '/api/collection', { path: p });
+      // Backend returns array of { id, data } OR bare data[]; normalize to
+      // { id, ...data } (firebase truth).
+      if (!Array.isArray(docs)) return [];
+      return docs.map(d => {
+        if (d && typeof d === 'object' && 'id' in d && 'data' in d) {
+          return { id: d.id, ...d.data };
+        }
+        return { ...d };
+      });
+    },
+
+    async batchWrite(ops) {
+      const normOps = ops.map(op => ({ ...op, path: norm(op.path) }));
+      await api('POST', '/api/batch', null, { ops: normOps });
+    },
+
+    subscribeDoc(rawPath, cb, errCb) {
+      const p = norm(rawPath);
+      // Initial value via REST (independent of WS connect). getDoc injects id.
+      storage.getDoc(p).then(cb).catch(() => {});
+      // WS only for subsequent change notifications.
+      ensureWs().then(() => {
+        ws.send(JSON.stringify({ type: 'subscribe', kind: 'doc', path: p }));
+      }).catch(() => {});
+      if (!docSubs.has(p)) docSubs.set(p, new Set());
+      docSubs.get(p).add(cb);
+      return () => { docSubs.get(p)?.delete(cb); };
+    },
+
+    subscribeCollection(rawCollPath, cb, queryConstraints = [], errCb) {
+      const p = norm(rawCollPath);
+      collConstraints.set(p, queryConstraints || []);
+      // Initial value via REST (independent of WS connect). Apply constraints
+      // client-side — backend returns all docs, adapter sorts/limits.
+      storage.getCollection(p)
+        .then(docs => cb(applyConstraints(docs, queryConstraints || [])))
+        .catch(() => {});
+      // WS only for subsequent change notifications.
+      ensureWs().then(() => {
+        ws.send(JSON.stringify({ type: 'subscribe', kind: 'collection', path: p }));
+      }).catch(() => {});
+      if (!collSubs.has(p)) collSubs.set(p, new Set());
+      collSubs.get(p).add(cb);
+      return () => { collSubs.get(p)?.delete(cb); };
+    },
+
+    dispose(cb) {
+      disposed = true;
+      if (reconnectTimer) { clearTimeout(reconnectTimer); reconnectTimer = null; }
+      if (ws) ws.close();
+      docSubs.clear(); collSubs.clear(); collConstraints.clear();
+      if (typeof cb === 'function') cb();
+    },
+
+    _api: api,
+    _test: {
+      getWs: () => ws,
+      forceDrop: () => { if (ws) ws.close(); },
+      getReady: () => wsReady,
+      docSubs, collSubs,
+    },
+  };
+
+  return storage;
+}
+
+export { createServerStorage };

src/tests/App.characterization.test.js

@@ -0,0 +1,142 @@
+// App.characterization.test.js
+// Characterize App -> Firebase calls. Lock path + payload shape per action.
+// Mock SDK, render AdminView, fire action, assert recorded calls.
+// Purpose: refactor (path-shape rewrite) must not change these calls.
+
+import React from 'react';
+import { screen, fireEvent, waitFor } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import { getCalls, MOCK_DB } from '../__mocks__/firebase/_mock-db';
+import { renderApp, createCampaignViaUI, selectCampaignByName } from './testHelpers';
+
+function findCall(fn, pathSub) {
+  return getCalls().find(c => c.fn === fn && (pathSub ? c.path.includes(pathSub) : true));
+}
+function findCalls(fn, pathSub) {
+  return getCalls().filter(c => c.fn === fn && (pathSub ? c.path.includes(pathSub) : true));
+}
+
+// ============================================================================
+// CAMPAIGN GROUP
+// ============================================================================
+
+describe('Campaign -> Firebase', () => {
+  test('createCampaign: setDoc with campaign path + payload', async () => {
+    await renderApp();
+    const id = await createCampaignViaUI('Alpha');
+    const call = findCall('setDoc', '/campaigns/');
+    expect(call.path).toMatch(/campaigns\/.+$/);
+    expect(call.data).toMatchObject({
+      name: 'Alpha',
+      playerDisplayBackgroundUrl: '',
+      players: [],
+    });
+    expect(call.data).toHaveProperty('ownerId');
+    expect(call.data).toHaveProperty('createdAt');
+  });
+
+  test('createCampaign: path includes APP_ID namespace', async () => {
+    await renderApp();
+    await createCampaignViaUI('NS Test');
+    const call = findCall('setDoc', '/campaigns/');
+    expect(call.path).toContain('artifacts/');
+    expect(call.path).toContain('/public/data/');
+  });
+
+  test('createCampaign: optional background URL stored', async () => {
+    await renderApp();
+    fireEvent.click(screen.getByRole('button', { name: /Create Campaign/i }));
+    await waitFor(() => screen.getByLabelText(/Campaign Name/i));
+    fireEvent.change(screen.getByLabelText(/Campaign Name/i), { target: { value: 'With BG' } });
+    fireEvent.change(screen.getByLabelText(/Background URL/i), { target: { value: 'https://img.test/bg.png' } });
+    fireEvent.click(screen.getByRole('button', { name: /^Create$/i }));
+    await waitFor(() => findCall('setDoc', '/campaigns/'));
+    const call = findCall('setDoc', '/campaigns/');
+    expect(call.data.playerDisplayBackgroundUrl).toBe('https://img.test/bg.png');
+  });
+
+  test('addCharacter: updateDoc on campaign doc, players array grows', async () => {
+    await renderApp();
+    const cid = await createCampaignViaUI('Roster');
+    await selectCampaignByName('Roster');
+
+    // CharacterManager form
+    fireEvent.change(screen.getByPlaceholderText('Character name'), { target: { value: 'Brog' } });
+    fireEvent.change(screen.getByLabelText(/Default HP/i), { target: { value: '25' } });
+    fireEvent.change(screen.getByLabelText(/Init Mod/i), { target: { value: '3' } });
+    fireEvent.click(screen.getByRole('button', { name: /Add Character/i }));
+
+    await waitFor(() => findCall('updateDoc', '/campaigns/'));
+    const call = findCall('updateDoc', `/campaigns/${cid}`);
+    expect(call.data.players).toHaveLength(1);
+    expect(call.data.players[0]).toMatchObject({
+      name: 'Brog',
+      defaultMaxHp: 25,
+      defaultInitMod: 3,
+    });
+    expect(call.data.players[0]).toHaveProperty('id');
+  });
+
+  test('updateCharacter: updateDoc with updated players array', async () => {
+    await renderApp();
+    const cid = await createCampaignViaUI('EditRoster');
+    await selectCampaignByName('EditRoster');
+
+    // add one first
+    fireEvent.change(screen.getByPlaceholderText('Character name'), { target: { value: 'Old Name' } });
+    fireEvent.click(screen.getByRole('button', { name: /Add Character/i }));
+    await waitFor(() => findCall('updateDoc', '/campaigns/'));
+
+    // click edit
+    const editBtn = await screen.findByRole('button', { name: /Edit character/i });
+    fireEvent.click(editBtn);
+    await waitFor(() => screen.getByDisplayValue('Old Name'));
+    fireEvent.change(screen.getByDisplayValue('Old Name'), { target: { value: 'New Name' } });
+    // Save button is icon-only (no text); submit its form.
+    const form = screen.getByDisplayValue('New Name').closest('form');
+    fireEvent.submit(form);
+
+    await waitFor(() => {
+      const calls = findCalls('updateDoc', `/campaigns/${cid}`);
+      const last = calls[calls.length - 1];
+      expect(last.data.players[0].name).toBe('New Name');
+    });
+  });
+
+  test('deleteCharacter: updateDoc with character removed', async () => {
+    await renderApp();
+    const cid = await createCampaignViaUI('DeleteRoster');
+    await selectCampaignByName('DeleteRoster');
+
+    fireEvent.change(screen.getByPlaceholderText('Character name'), { target: { value: 'Gone' } });
+    fireEvent.click(screen.getByRole('button', { name: /Add Character/i }));
+    await waitFor(() => findCall('updateDoc', '/campaigns/'));
+
+    const delBtn = await screen.findByRole('button', { name: /Delete character/i });
+    fireEvent.click(delBtn);
+    // confirmation modal
+    fireEvent.click(screen.getByRole('button', { name: /Confirm/i }));
+
+    await waitFor(() => {
+      const calls = findCalls('updateDoc', `/campaigns/${cid}`);
+      const last = calls[calls.length - 1];
+      expect(last.data.players).toHaveLength(0);
+    });
+  });
+
+  test('deleteCampaign: deletes encounters batch + campaign doc + activeDisplay null', async () => {
+    await renderApp();
+    const cid = await createCampaignViaUI('Doomed');
+    await selectCampaignByName('Doomed');
+
+    // campaign card delete button has no aria-label; find trash by text via grid
+    const allDeletes = screen.getAllByText(/Delete/i);
+    // campaign card Delete is in card grid, last one rendered
+    fireEvent.click(allDeletes[allDeletes.length - 1]);
+    fireEvent.click(await screen.findByRole('button', { name: /Confirm/i }));
+
+    await waitFor(() => findCall('deleteDoc', `/campaigns/${cid}`));
+    const delCall = findCall('deleteDoc', `/campaigns/${cid}`);
+    expect(delCall).toBeDefined();
+  });
+});

src/tests/Combat.characterization.test.js

@@ -0,0 +1,139 @@
+// Combat characterization. Lock updateDoc/setDoc patch for combat controls.
+
+import React from 'react';
+import { screen, fireEvent, waitFor } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import { getCalls } from '../__mocks__/firebase/_mock-db';
+import { setupReady, addMonsterViaUI, startCombatViaUI } from './testHelpers';
+
+function findCallsEnc() {
+  return getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/'));
+}
+function lastEncCall() {
+  const calls = findCallsEnc();
+  return calls[calls.length - 1];
+}
+function findCallActiveDisplay(fn) {
+  return getCalls().filter(c => c.fn === fn && c.path.includes('activeDisplay/status'));
+}
+
+async function setupWithMonsters(names = ['A', 'B', 'C']) {
+  await setupReady('CombatCamp', 'CombatEnc');
+  for (const n of names) {
+    await addMonsterViaUI(n, 20, Number(n.charCodeAt(0) % 10));
+  }
+}
+
+describe('Combat -> Firebase', () => {
+  test('startEncounter: updateDoc sets isStarted/round/turn/current', async () => {
+    await setupWithMonsters();
+    await startCombatViaUI();
+    const call = lastEncCall();
+    expect(call.data).toMatchObject({
+      isStarted: true,
+      isPaused: false,
+      round: 1,
+    });
+    expect(call.data.currentTurnParticipantId).toBeTruthy();
+    expect(call.data.turnOrderIds).toHaveLength(3);
+  });
+
+  test('startEncounter: also sets activeDisplay to this encounter', async () => {
+    await setupWithMonsters();
+    await startCombatViaUI();
+    const adCalls = findCallActiveDisplay('setDoc');
+    const last = adCalls[adCalls.length - 1];
+    expect(last.data.activeCampaignId).toBeTruthy();
+    expect(last.data.activeEncounterId).toBeTruthy();
+  });
+
+  test('nextTurn: advances currentTurnParticipantId', async () => {
+    await setupWithMonsters();
+    await startCombatViaUI();
+    const beforeId = lastEncCall().data.currentTurnParticipantId;
+
+    fireEvent.click(screen.getByRole('button', { name: /Next Turn/i }));
+    await waitFor(() => lastEncCall()?.data?.currentTurnParticipantId !== beforeId);
+    expect(lastEncCall().data.currentTurnParticipantId).not.toBe(beforeId);
+  });
+
+  test('nextTurn wrapping to round 1->2 increments round', async () => {
+    await setupWithMonsters(['A', 'B']);
+    await startCombatViaUI();
+
+    // advance through all participants to wrap
+    fireEvent.click(screen.getByRole('button', { name: /Next Turn/i })); // A->B (or 2nd)
+    await waitFor(() => lastEncCall()?.data?.currentTurnParticipantId);
+    fireEvent.click(screen.getByRole('button', { name: /Next Turn/i })); // wrap
+    await waitFor(() => lastEncCall()?.data?.round === 2);
+    expect(lastEncCall().data.round).toBe(2);
+  });
+
+  test('pause: updateDoc sets isPaused true', async () => {
+    await setupWithMonsters();
+    await startCombatViaUI();
+    fireEvent.click(screen.getByRole('button', { name: /Pause Combat/i }));
+    await waitFor(() => lastEncCall()?.data?.isPaused === true);
+    expect(lastEncCall().data.isPaused).toBe(true);
+  });
+
+  test('resume: updateDoc sets isPaused false + recomputes turnOrder', async () => {
+    await setupWithMonsters();
+    await startCombatViaUI();
+    fireEvent.click(screen.getByRole('button', { name: /Pause Combat/i }));
+    await waitFor(() => lastEncCall()?.data?.isPaused === true);
+    fireEvent.click(screen.getByRole('button', { name: /Resume Combat/i }));
+    await waitFor(() => lastEncCall()?.data?.isPaused === false);
+    const call = lastEncCall();
+    expect(call.data.isPaused).toBe(false);
+    expect(call.data.turnOrderIds).toHaveLength(3);
+  });
+
+  test('endEncounter: updateDoc resets all combat state', async () => {
+    await setupWithMonsters();
+    await startCombatViaUI();
+    fireEvent.click(screen.getByRole('button', { name: /End Combat/i }));
+    fireEvent.click(await screen.findByRole('button', { name: /Confirm/i }));
+    await waitFor(() => lastEncCall()?.data?.isStarted === false);
+    const call = lastEncCall();
+    expect(call.data).toMatchObject({
+      isStarted: false,
+      isPaused: false,
+      round: 0,
+      currentTurnParticipantId: null,
+      turnOrderIds: [],
+    });
+  });
+
+  test('endEncounter: clears activeDisplay', async () => {
+    await setupWithMonsters();
+    await startCombatViaUI();
+    fireEvent.click(screen.getByRole('button', { name: /End Combat/i }));
+    fireEvent.click(await screen.findByRole('button', { name: /Confirm/i }));
+    await waitFor(() => {
+      const adCalls = findCallActiveDisplay('setDoc');
+      const last = adCalls[adCalls.length - 1];
+      return last && last.data.activeCampaignId === null;
+    });
+    const adCalls = findCallActiveDisplay('setDoc');
+    const last = adCalls[adCalls.length - 1];
+    expect(last.data).toMatchObject({ activeCampaignId: null, activeEncounterId: null });
+  });
+
+  test('toggleHidePlayerHp: setDoc{merge} patch on activeDisplay/status', async () => {
+    await setupWithMonsters();
+    await startCombatViaUI();
+    // Two switches now (Hide player HP + Hide NPC/monster HP). Scope to player one.
+    const playerHpLabel = screen.getByText('Hide player HP');
+    const switchBtn = playerHpLabel.parentElement.querySelector('[role="switch"]');
+    fireEvent.click(switchBtn);
+    await waitFor(() => {
+      const adCalls = findCallActiveDisplay('setDoc');
+      const last = adCalls[adCalls.length - 1];
+      return last && 'hidePlayerHp' in last.data;
+    });
+    const adCalls = findCallActiveDisplay('setDoc');
+    const last = adCalls[adCalls.length - 1];
+    expect(last.data).toHaveProperty('hidePlayerHp');
+  });
+});

src/tests/Combat.scenario.test.js

@@ -0,0 +1,334 @@
+// Combat.scenario.test.js
+// Full combat scenario driven through shared/turn.js directly --- NO React.
+//
+// Does 100 ROUNDS (not turns). A round = one full pass through initiative
+// (every active participant acts once); round counter increments at wrap.
+// See docs/GLOSSARY.md. Previous version lied: called nextTurn 100× (~100
+// turns, ~12 rounds). Now loops by actual round-wrap count.
+//
+// Exercises ALL combat paths deterministically (less random than replay):
+//   startEncounter, nextTurn, togglePause, addParticipant, addParticipants,
+//   updateParticipant, removeParticipant, toggleParticipantActive,
+//   applyHpChange (damage/heal), deathSave (incl. 3-success → isDying),
+//   toggleCondition, reorderParticipants (drag same-init tie), endEncounter,
+//   activateDisplay, clearDisplay, toggleHidePlayerHp.
+//
+// Failing assertions do NOT abort the run: each phase wrapped in try/catch,
+// failures collected, final expect reports all.
+
+const {
+  makeParticipant,
+  buildCharacterParticipant,
+  buildMonsterParticipant,
+  startEncounter,
+  nextTurn,
+  togglePause,
+  addParticipant,
+  addParticipants,
+  updateParticipant,
+  removeParticipant,
+  toggleParticipantActive,
+  applyHpChange,
+  deathSave,
+  toggleCondition,
+  reorderParticipants,
+  endEncounter,
+  activateDisplay,
+  clearDisplay,
+  toggleHidePlayerHp,
+} = require('../../shared');
+
+// aliases for combat funcs that clash with local helper names
+const {
+  applyHpChange: combatApplyHpChange,
+  toggleParticipantActive: combatToggleActive,
+  toggleCondition: combatToggleCondition,
+  deathSave: combatDeathSave,
+} = require('../../shared');
+
+// ---------- scenario state (mirrors two firestore docs) ----------
+
+const ROUNDS = 100;
+
+// encounter doc
+let enc = {
+  name: 'BigBoss',
+  participants: [],
+  isStarted: false,
+  isPaused: false,
+  round: 0,
+  currentTurnParticipantId: null,
+  turnOrderIds: [],
+};
+// activeDisplay/status doc
+let display = {
+  activeCampaignId: null,
+  activeEncounterId: null,
+  hidePlayerHp: true,
+  hideNpcHp: false,
+};
+const CAMPAIGN_ID = 'camp-1';
+const ENCOUNTER_ID = 'enc-1';
+const roster = [];
+
+function applyEnc(patch) {
+  if (!patch) return;
+  for (const [k, v] of Object.entries(patch)) enc[k] = v;
+}
+function applyDisplay(patch) {
+  if (!patch) return;
+  for (const [k, v] of Object.entries(patch)) display[k] = v;
+}
+
+const RESULTS = [];
+function record(phase, fn) {
+  try { fn(); RESULTS.push({ phase, ok: true }); }
+  catch (err) { RESULTS.push({ phase, ok: false, err: err.message }); }
+}
+async function recordAsync(phase, fn) {
+  try { await fn(); RESULTS.push({ phase, ok: true }); }
+  catch (err) { RESULTS.push({ phase, ok: false, err: err.message }); }
+}
+
+// ---------- helpers (shared, no React) ----------
+
+const alive = (name) => enc.participants.find(p => p.name === name && p.currentHp > 0);
+const any = (name) => enc.participants.find(p => p.name === name);
+const idOf = (name) => { const p = any(name); return p ? p.id : null; };
+
+function addCharacterViaUI(name, maxHp, initMod) {
+  roster.push({ id: `char-${name}`, name, defaultMaxHp: maxHp, defaultInitMod: initMod });
+}
+function addMonsterParticipant(name, maxHp, initMod, isNpc = false) {
+  const { participant } = buildMonsterParticipant({ name, maxHp, initMod, isNpc });
+  applyEnc(addParticipant(enc, participant).patch);
+}
+function addCharacterParticipant(charName) {
+  const character = roster.find(c => c.name === charName);
+  if (!character) throw new Error(`char not found: ${charName}`);
+  if (enc.participants.some(p => p.type === 'character' && p.originalCharacterId === character.id)) {
+    throw new Error(`${charName} already in encounter`);
+  }
+  const { participant } = buildCharacterParticipant(character);
+  applyEnc(addParticipant(enc, participant).patch);
+}
+function addAllCharacters() {
+  const toAdd = roster
+    .filter(c => !enc.participants.some(p => p.type === 'character' && p.originalCharacterId === c.id))
+    .map(c => buildCharacterParticipant(c).participant);
+  applyEnc(addParticipants(enc, toAdd).patch);
+}
+function startCombat() {
+  applyEnc(startEncounter(enc).patch);
+  applyDisplay(activateDisplay({ campaignId: CAMPAIGN_ID, encounterId: ENCOUNTER_ID }).patch);
+}
+function endCombat() {
+  applyEnc(endEncounter(enc).patch);
+  applyDisplay(clearDisplay().patch);
+}
+function nextTurnAction() { applyEnc(nextTurn(enc).patch); }
+function pauseCombat() { applyEnc(togglePause(enc).patch); if (!enc.isPaused) throw new Error('not paused'); }
+function resumeCombat() { applyEnc(togglePause(enc).patch); if (enc.isPaused) throw new Error('not resumed'); }
+
+function applyDamage(name, amount) {
+  const p = any(name);
+  if (!p || p.currentHp <= 0) return; // dead = skip (button hidden in UI)
+  applyEnc(combatApplyHpChange(enc, p.id, 'damage', amount).patch);
+}
+function applyHeal(name, amount) {
+  const p = any(name);
+  if (!p) return; // removed (death) = skip (no button in UI)
+  applyEnc(combatApplyHpChange(enc, p.id, 'heal', amount).patch);
+}
+function toggleActive(name) {
+  const p = any(name);
+  if (!p) throw new Error(`no active target: ${name}`);
+  applyEnc(combatToggleActive(enc, p.id).patch);
+}
+function toggleConditionAction(name, label) {
+  const p = any(name);
+  if (!p) throw new Error(`no condition target: ${name}`);
+  applyEnc(combatToggleCondition(enc, p.id, label).patch);
+}
+function editParticipant(name, patch) {
+  const p = any(name);
+  if (!p) throw new Error(`no edit target: ${name}`);
+  applyEnc(updateParticipant(enc, p.id, patch).patch);
+}
+function removeParticipantByName(name) {
+  const p = any(name);
+  if (!p) throw new Error(`no remove target: ${name}`);
+  applyEnc(removeParticipant(enc, p.id).patch);
+}
+function deathSaveAction(name, type, saveNum) {
+  const p = any(name);
+  if (!p) throw new Error(`no deathsave target: ${name}`);
+  applyEnc(combatDeathSave(enc, p.id, type, saveNum).patch);
+}
+function dragTie(draggedName, targetName) {
+  const d = any(draggedName), t = any(targetName);
+  if (!d || !t) throw new Error('drag target missing');
+  applyEnc(reorderParticipants(enc, d.id, t.id).patch);
+}
+function toggleHidePlayerHpAction() {
+  applyDisplay(toggleHidePlayerHp(display.hidePlayerHp).patch);
+}
+
+// ---------- scenario ----------
+
+test('full 100-round combat scenario (shared, no React)', async () => {
+  // roster
+  await recordAsync('addChar Fighter', () => addCharacterViaUI('Fighter', 30, 2));
+  await recordAsync('addChar Cleric', () => addCharacterViaUI('Cleric', 24, 1));
+  await recordAsync('addChar Rogue', () => addCharacterViaUI('Rogue', 22, 3));
+
+  // monsters + npcs
+  await recordAsync('addMonster Goblin1', () => addMonsterParticipant('Goblin1', 8, 2));
+  await recordAsync('addMonster Goblin2', () => addMonsterParticipant('Goblin2', 8, 2));
+  await recordAsync('addMonster OrcBoss', () => addMonsterParticipant('OrcBoss', 60, 1));
+  await recordAsync('addMonster Wolf', () => addMonsterParticipant('Wolf', 14, 3));
+  await recordAsync('addNpc Merchant', () => addMonsterParticipant('Merchant', 12, 0, true));
+
+  // add chars into encounter
+  await recordAsync('addCharParticipant Fighter', () => addCharacterParticipant('Fighter'));
+  await recordAsync('addCharParticipant Cleric', () => addCharacterParticipant('Cleric'));
+  await recordAsync('addCharParticipant Rogue', () => addCharacterParticipant('Rogue'));
+  await recordAsync('addAllChars', () => addAllCharacters()); // bulk add path
+
+  // hidden hp toggle x2 (back to default)
+  record('toggleHidePlayerHp', () => toggleHidePlayerHpAction());
+  record('toggleHidePlayerHp back', () => toggleHidePlayerHpAction());
+
+  await recordAsync('startCombat', () => startCombat());
+
+  // ---------- 100 ROUNDS (loop by actual round-wrap count) ----------
+  let roundsDone = 0;
+  let prevRound = enc.round;
+  let turnInRound = 0;
+  let turnTotal = 0;
+
+  while (roundsDone < ROUNDS) {
+    turnTotal++;
+    const actor = anyById(enc.currentTurnParticipantId);
+    const r = enc.round;
+
+    // per-turn deterministic actions keyed by round + actor type
+    // damage OrcBoss every even round
+    if (r % 2 === 0 && turnInRound === 0) {
+      await recordAsync(`r${r} damage OrcBoss`, () => applyDamage('OrcBoss', 3));
+    }
+    // heal Cleric every 3 rounds
+    if (r % 3 === 0 && turnInRound === 1) {
+      record(`r${r} heal Cleric`, () => applyHeal('Cleric', 2));
+    }
+    // condition on Fighter every 5 rounds
+    if (r % 5 === 0 && turnInRound === 2) {
+      record(`r${r} condition Fighter stunned`, () => toggleConditionAction('Fighter', 'Stunned'));
+    }
+    // toggleActive Goblin2 every 7 rounds (toggle off, next 7 toggle on)
+    if (r % 7 === 0 && turnInRound === 3) {
+      record(`r${r} toggleActive Goblin2`, () => toggleActive('Goblin2'));
+    }
+    // edit Wolf initiative every 13 rounds
+    if (r % 13 === 0 && turnInRound === 4) {
+      record(`r${r} edit Wolf init`, () => editParticipant('Wolf', { initiative: 15 }));
+    }
+
+    // pause/resume + add reinforcement + edit every 10 rounds
+    if (r % 10 === 0 && turnInRound === 0) {
+      await recordAsync(`r${r} pause`, () => pauseCombat());
+      await recordAsync(`r${r} addReinforcement`, () => addMonsterParticipant(`Reinforce${r}`, 10, 1));
+      await recordAsync(`r${r} edit Rogue initiative`, () => editParticipant('Rogue', { initiative: 20 }));
+      await recordAsync(`r${r} resume`, () => resumeCombat());
+    }
+
+    // create a same-init tie + drag every 15 rounds (exercises reorderParticipants)
+    if (r % 15 === 0 && turnInRound === 5) {
+      const g1 = any('Goblin1');
+      if (g1 && alive('Goblin2')) {
+        record(`r${r} tie Goblin2->Goblin1 init`, () => editParticipant('Goblin2', { initiative: g1.initiative }));
+        record(`r${r} drag Goblin2 before Goblin1`, () => dragTie('Goblin2', 'Goblin1'));
+      }
+    }
+
+    // death scenarios: drop a PC to 0, death saves, revive
+    if (r === 25 && turnInRound === 0) {
+      await recordAsync(`r${r} drop Rogue`, () => applyDamage('Rogue', 99));
+      record(`r${r} deathSave1 Rogue`, () => deathSaveAction('Rogue', 'fail', 1));
+      record(`r${r} revive Rogue`, () => applyHeal('Rogue', 22));
+    }
+    // round 50: full 3-success death-save path (isDying) on Cleric, then remove
+    if (r === 50 && turnInRound === 0) {
+      await recordAsync(`r${r} drop Cleric`, () => applyDamage('Cleric', 99));
+      await recordAsync(`r${r} deathSave Cleric x3 (isDying)`, async () => {
+        deathSaveAction('Cleric', 'fail', 1);
+        deathSaveAction('Cleric', 'fail', 2);
+        deathSaveAction('Cleric', 'fail', 3); // → dead
+      });
+      const cl = any('Cleric');
+      if (cl && cl.isDying) record(`r${r} remove dying Cleric`, () => removeParticipantByName('Cleric'));
+    }
+
+    // remove a reinforcement every 30 rounds
+    if (r % 30 === 0 && turnInRound === 1) {
+      const rein = any(`Reinforce${r - 10}`);
+      if (rein) record(`r${r} remove Reinforce${r - 10}`, () => removeParticipantByName(`Reinforce${r - 10}`));
+    }
+
+    // toggle hide hp every 20 rounds
+    if (r % 20 === 0 && turnInRound === 0) {
+      record(`r${r} toggleHidePlayerHp`, () => toggleHidePlayerHpAction());
+      record(`r${r} toggleHidePlayerHp back`, () => toggleHidePlayerHpAction());
+    }
+
+    // rotation integrity check every 10 rounds at round start
+    if (turnInRound === 0 && r % 10 === 0) {
+      record(`r${r} rotation-check`, () => {
+        const order = enc.turnOrderIds || [];
+        const uniq = new Set(order);
+        if (uniq.size !== order.length) throw new Error(`turnOrderIds dup: ${JSON.stringify(order)}`);
+        if (enc.currentTurnParticipantId && !order.includes(enc.currentTurnParticipantId)) {
+          throw new Error(`currentTurn ${enc.currentTurnParticipantId} not in turnOrderIds`);
+        }
+        const ids = enc.participants.map(p => p.id);
+        if (JSON.stringify(order) !== JSON.stringify(ids)) {
+          throw new Error(`turnOrderIds drift: order=${JSON.stringify(order)} ids=${JSON.stringify(ids)}`);
+        }
+      });
+    }
+
+    // advance turn
+    await recordAsync(`r${r} turn${turnInRound} nextTurn`, () => nextTurnAction());
+    turnInRound++;
+
+    // round wrap detected
+    if (enc.round > prevRound) {
+      roundsDone++;
+      prevRound = enc.round;
+      turnInRound = 0;
+    }
+  }
+
+  await recordAsync('endCombat', () => endCombat());
+
+  // ---------- report ----------
+  const failed = RESULTS.filter(x => !x.ok);
+  if (failed.length > 0) {
+    const msg = failed.map(f => `FAIL [${f.phase}]: ${f.err}`).join('\n');
+    // eslint-disable-next-line no-console
+    console.error(`\n=== SCENARIO FAILURES (${failed.length}/${RESULTS.length}) ===\n${msg}\n`);
+  }
+  expect(failed).toEqual([]);
+  expect(roundsDone).toBe(ROUNDS);
+
+  // lifecycle assertions (activeDisplay mirrors combat state)
+  expect(enc.isStarted).toBe(false);
+  expect(enc.round).toBe(0);
+  expect(enc.currentTurnParticipantId).toBeNull();
+  expect(display.activeCampaignId).toBeNull();
+  expect(display.activeEncounterId).toBeNull();
+});
+
+function anyById(id) {
+  return enc.participants.find(p => p.id === id);
+}

src/tests/DisplayView.characterization.test.js

@@ -0,0 +1,60 @@
+// DisplayView.characterization.test.js
+// Lock DisplayView uses storage adapter (subscribeDoc), NOT raw SDK onSnapshot(doc(db)).
+// Blind spot caught: M2 refactor missed DisplayView; raw SDK + ws stub db = crash.
+// Test asserts adapter recorder shows subscribeDoc calls when player view boots.
+
+import React from 'react';
+import { render, waitFor } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import App from '../App';
+import { MOCK_DB } from '../__mocks__/firebase/_mock-db';
+import { getAdapterCalls, resetAdapterCalls } from '../storage/firebase';
+
+// Seed activeDisplay + campaign + encounter so DisplayView has data to subscribe to.
+function seedActiveDisplay() {
+  const campaignPath = 'artifacts/ttrpg-initiative-tracker-default/public/data/campaigns/c1';
+  const encounterPath = 'artifacts/ttrpg-initiative-tracker-default/public/data/campaigns/c1/encounters/e1';
+  const activeDisplayPath = 'artifacts/ttrpg-initiative-tracker-default/public/data/activeDisplay/status';
+
+  MOCK_DB.set(campaignPath, { name: 'Camp', playerDisplayBackgroundUrl: '' });
+  MOCK_DB.set(encounterPath, { name: 'Enc', participants: [], isStarted: true });
+  MOCK_DB.set(activeDisplayPath, { activeCampaignId: 'c1', activeEncounterId: 'e1', hidePlayerHp: false });
+}
+
+describe('DisplayView characterization', () => {
+  beforeEach(() => {
+    window.history.replaceState({}, '', '/display');
+    global.alert = jest.fn();
+    window.open = jest.fn();
+    resetAdapterCalls();
+  });
+  afterEach(() => {
+    window.history.replaceState({}, '', '/');
+  });
+
+  test('DisplayView subscribes via adapter.subscribeDoc (not raw SDK)', async () => {
+    seedActiveDisplay();
+    render(<App />);
+
+    // wait for DisplayView to mount and attempt subscriptions
+    await waitFor(() => {
+      const subs = getAdapterCalls().filter(c => c.fn === 'subscribeDoc');
+      expect(subs.length).toBeGreaterThanOrEqual(1);
+    }, { timeout: 3000 });
+
+    // must subscribe to campaign doc (for background url) and encounter doc
+    const docSubs = getAdapterCalls().filter(c => c.fn === 'subscribeDoc').map(c => c.path);
+    expect(docSubs.some(p => p.includes('/campaigns/c1'))).toBe(true);
+    expect(docSubs.some(p => p.includes('/encounters/e1'))).toBe(true);
+  });
+
+  test('DisplayView also subscribes to activeDisplay status doc via adapter', async () => {
+    seedActiveDisplay();
+    render(<App />);
+
+    await waitFor(() => {
+      const subs = getAdapterCalls().filter(c => c.fn === 'subscribeDoc' && c.path.includes('activeDisplay'));
+      expect(subs.length).toBeGreaterThanOrEqual(1);
+    }, { timeout: 3000 });
+  });
+});

src/tests/DisplayView.drag-order.test.js

@@ -0,0 +1,63 @@
+// RED test: DisplayView must render participants in turnOrderIds (drag) order,
+// NOT re-sort by initiative. 1-list model: participants[] = display source.
+// Bug: DisplayView line ~2505 calls sortParticipantsByInitiative(), ignoring
+// DM drag order. After cross-init drag, display diverges from AdminView/turnOrderIds.
+import React from 'react';
+import { render, waitFor, screen } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import App from '../App';
+import { MOCK_DB } from '../__mocks__/firebase/_mock-db';
+import { resetAdapterCalls } from '../storage/firebase';
+
+function seedDragOrder() {
+  const campaignPath = 'artifacts/ttrpg-initiative-tracker-default/public/data/campaigns/c1';
+  const encounterPath = 'artifacts/ttrpg-initiative-tracker-default/public/data/campaigns/c1/encounters/e1';
+  const activeDisplayPath = 'artifacts/ttrpg-initiative-tracker-default/public/data/activeDisplay/status';
+  // Three monsters, init-sorted would be: high(20), mid(11), low(10).
+  // But participants[] = DRAG order: low BEFORE mid (DM dragged across init).
+  const participants = [
+    { id: 'high', name: 'High', type: 'monster', initiative: 20, currentHp: 10, maxHp: 10, isActive: true },
+    { id: 'low', name: 'Low', type: 'monster', initiative: 10, currentHp: 10, maxHp: 10, isActive: true },
+    { id: 'mid', name: 'Mid', type: 'monster', initiative: 11, currentHp: 10, maxHp: 10, isActive: true },
+  ];
+  MOCK_DB.set(campaignPath, { name: 'Camp', playerDisplayBackgroundUrl: '' });
+  MOCK_DB.set(encounterPath, {
+    name: 'Enc',
+    participants,
+    turnOrderIds: participants.map(p => p.id),
+    round: 1,
+    currentTurnParticipantId: 'high',
+    isStarted: true,
+  });
+  MOCK_DB.set(activeDisplayPath, { activeCampaignId: 'c1', activeEncounterId: 'e1', hidePlayerHp: false });
+}
+
+describe('DisplayView drag order (BUG-15)', () => {
+  beforeEach(() => {
+    window.history.replaceState({}, '', '/display');
+    global.alert = jest.fn();
+    window.open = jest.fn();
+    // jsdom lacks scrollIntoView (DisplayView auto-scrolls current actor)
+    Element.prototype.scrollIntoView = jest.fn();
+    resetAdapterCalls();
+  });
+  afterEach(() => {
+    window.history.replaceState({}, '', '/');
+  });
+
+  test('renders participants in participants[] order, not init-sorted', async () => {
+    seedDragOrder();
+    render(<App />);
+
+    // wait for participant names to render
+    await waitFor(() => {
+      expect(screen.getAllByText(/High|Mid|Low/i).length).toBeGreaterThanOrEqual(3);
+    }, { timeout: 3000 });
+
+    // collect name elements in DOM order (strip Current marker)
+    const names = screen.getAllByText(/High|Mid|Low/i).map(el => el.textContent.replace(/\(Current\)/i, '').trim());
+    // participants[] order = High, Low, Mid (drag moved Low before Mid).
+    // Display must mirror this. Init-sorted would be High, Mid, Low.
+    expect(names).toEqual(['High', 'Low', 'Mid']);
+  });
+});

src/tests/Encounter.characterization.test.js

@@ -0,0 +1,122 @@
+// Encounter characterization. Lock setDoc path + payload on encounter actions.
+
+import React from 'react';
+import { screen, fireEvent, waitFor } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import { getCalls } from '../__mocks__/firebase/_mock-db';
+import { renderApp, createCampaignViaUI, selectCampaignByName, createEncounterViaUI, selectEncounterByName } from './testHelpers';
+
+function findCall(fn, pathSub) {
+  return getCalls().find(c => c.fn === fn && (pathSub ? c.path.includes(pathSub) : true));
+}
+function findCalls(fn, pathSub) {
+  return getCalls().filter(c => c.fn === fn && (pathSub ? c.path.includes(pathSub) : true));
+}
+
+async function setupCampaignAndEncounter(campName, encName) {
+  await renderApp();
+  await createCampaignViaUI(campName);
+  await selectCampaignByName(campName);
+  await createEncounterViaUI(encName);
+}
+
+describe('Encounter -> Firebase', () => {
+  test('createEncounter: setDoc with encounter path + payload', async () => {
+    await setupCampaignAndEncounter('Camp E', 'Boss Fight');
+    const call = findCall('setDoc', '/encounters/');
+    expect(call.path).toMatch(/encounters\/.+$/);
+    expect(call.data).toMatchObject({
+      name: 'Boss Fight',
+      participants: [],
+      round: 0,
+      currentTurnParticipantId: null,
+      isStarted: false,
+      isPaused: false,
+    });
+    expect(call.data).toHaveProperty('createdAt');
+  });
+
+  test('createEncounter: path nested under campaign', async () => {
+    await setupCampaignAndEncounter('Camp N', 'Enc N');
+    const call = findCall('setDoc', '/encounters/');
+    expect(call.path).toMatch(/campaigns\/[^/]+\/encounters\//);
+  });
+
+  test('togglePlayerDisplay: setDoc{merge} patch on activeDisplay/status', async () => {
+    await setupCampaignAndEncounter('Camp D', 'Enc D');
+    await selectEncounterByName('Enc D');
+
+    // Eye button (icon-only, title attr)
+    const eyeBtn = await screen.findByTitle('Activate for Player Display');
+    fireEvent.click(eyeBtn);
+
+    await waitFor(() => findCall('setDoc', 'activeDisplay/status'));
+    const call = findCall('setDoc', 'activeDisplay/status');
+    // main truth: setDoc{merge} patch, not replace (would clobber fields)
+    expect(call.data).toMatchObject({
+      activeCampaignId: expect.any(String),
+      activeEncounterId: expect.any(String),
+    });
+  });
+
+  test('togglePlayerDisplay off: setDoc{merge} nulls active ids', async () => {
+    await setupCampaignAndEncounter('Camp O', 'Enc O');
+    await selectEncounterByName('Enc O');
+
+    // turn ON
+    const onBtn = await screen.findByTitle('Activate for Player Display');
+    fireEvent.click(onBtn);
+    await waitFor(() => findCall('setDoc', 'activeDisplay/status'));
+
+    // turn OFF
+    const offBtn = await screen.findByTitle('Deactivate for Player Display');
+    fireEvent.click(offBtn);
+    await waitFor(() => {
+      const calls = findCalls('setDoc', 'activeDisplay/status');
+      const last = calls[calls.length - 1];
+      return last.data.activeCampaignId === null;
+    });
+    const calls = findCalls('setDoc', 'activeDisplay/status');
+    const last = calls[calls.length - 1];
+    expect(last.data).toMatchObject({ activeCampaignId: null, activeEncounterId: null });
+  });
+
+  test('deleteEncounter: deleteDoc on encounter path', async () => {
+    await setupCampaignAndEncounter('Camp X', 'Enc X');
+    await selectEncounterByName('Enc X');
+
+    // trash icon on encounter card
+    const trashBtn = screen.getAllByTitle('Delete Encounter')[0];
+    fireEvent.click(trashBtn);
+    // confirm modal
+    fireEvent.click(await screen.findByRole('button', { name: /Confirm/i }));
+
+    await waitFor(() => findCall('deleteDoc', '/encounters/'));
+    const del = findCall('deleteDoc', '/encounters/');
+    expect(del.path).toMatch(/campaigns\/[^/]+\/encounters\//);
+  });
+
+  test('deleteEncounter clears activeDisplay if it was active', async () => {
+    await setupCampaignAndEncounter('Camp A', 'Enc A');
+    await selectEncounterByName('Enc A');
+
+    // activate display first
+    const onBtn = await screen.findByTitle('Activate for Player Display');
+    fireEvent.click(onBtn);
+    await waitFor(() => findCall('updateDoc', 'activeDisplay/status'));
+
+    // delete the active encounter
+    const trashBtn = screen.getAllByTitle('Delete Encounter')[0];
+    fireEvent.click(trashBtn);
+    fireEvent.click(await screen.findByRole('button', { name: /Confirm/i }));
+
+    await waitFor(() => {
+      const adCalls = findCalls('updateDoc', 'activeDisplay/status');
+      const last = adCalls[adCalls.length - 1];
+      return last.data.activeEncounterId === null;
+    });
+    const adCalls = findCalls('updateDoc', 'activeDisplay/status');
+    const last = adCalls[adCalls.length - 1];
+    expect(last.data).toMatchObject({ activeCampaignId: null, activeEncounterId: null });
+  });
+});

src/tests/HideHpToggle.test.js

@@ -0,0 +1,65 @@
+// BUG-4 repro: toggling hidePlayerHp must not clobber activeDisplay doc.
+// setDoc = replace would clobber. setDoc({merge:true}) patches only — matches main.
+// Toggling hide-HP writes {hidePlayerHp:X} via setDoc{merge} → activeCampaignId + activeEncounterId preserved.
+// Display keeps reading them → stays active.
+// Regression: if caller swaps to plain setDoc (no merge) or updateDoc-throws-on-missing, re-breaks.
+
+import React from 'react';
+import { render, waitFor, screen, fireEvent } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import App from '../App';
+import { MOCK_DB } from '../__mocks__/firebase/_mock-db';
+import { getAdapterCalls, resetAdapterCalls } from '../storage/firebase';
+import { selectCampaignByName } from './testHelpers';
+
+function seedAdminWithActiveEncounter() {
+  const campaignPath = 'artifacts/ttrpg-initiative-tracker-default/public/data/campaigns/c1';
+  const encounterPath = 'artifacts/ttrpg-initiative-tracker-default/public/data/campaigns/c1/encounters/e1';
+  const activeDisplayPath = 'artifacts/ttrpg-initiative-tracker-default/public/data/activeDisplay/status';
+
+  MOCK_DB.set(campaignPath, { name: 'Camp', playerDisplayBackgroundUrl: '' });
+  MOCK_DB.set(encounterPath, { name: 'Enc', participants: [], isStarted: true });
+  // active encounter set, HP NOT hidden
+  MOCK_DB.set(activeDisplayPath, {
+    activeCampaignId: 'c1',
+    activeEncounterId: 'e1',
+    hidePlayerHp: false,
+  });
+}
+
+describe('BUG-4: hide-player-HP toggle preserves activeDisplay', () => {
+  beforeEach(() => {
+    window.history.replaceState({}, '', '/');
+    global.alert = jest.fn();
+    resetAdapterCalls();
+  });
+
+  test('toggling hidePlayerHp does NOT clear activeCampaignId/activeEncounterId', async () => {
+    seedAdminWithActiveEncounter();
+    render(<App />);
+
+    // wait for admin to mount + load active display
+    await waitFor(() => screen.getByText('Camp'), { timeout: 3000 });
+    await selectCampaignByName('Camp');
+
+    // find the hide-player-HP toggle (role switch)
+    const toggle = await screen.findByRole('switch', { name: /hide player hp/i }, { timeout: 3000 });
+
+    // toggle ON
+    fireEvent.click(toggle);
+
+    await waitFor(() => {
+      const writes = getAdapterCalls().filter(
+        c => c.fn === 'setDoc' && c.path.includes('activeDisplay/status')
+      );
+      expect(writes.length).toBeGreaterThan(0);
+      const last = writes[writes.length - 1];
+      // merge flag MUST be present — else plain setDoc clobbers other fields.
+      expect(last.opts && last.opts.merge).toBe(true);
+      // patch must NOT clobber activeCampaignId/activeEncounterId.
+      // BUG: setDoc replace writes only {hidePlayerHp:true} → clobbers.
+      // Fix: setDoc{merge} patch — other fields untouched.
+      expect(last.data.hidePlayerHp).toBe(true);
+    }, { timeout: 3000 });
+  });
+});

src/tests/InitiativeField.test.js

@@ -0,0 +1,57 @@
+// RED test: FEAT-3 initiative field on add participant.
+// If initiative field set, use it (no roll). Empty = roll d20+mod (current).
+import React from 'react';
+import { screen, waitFor, within } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import { renderApp, createCampaignViaUI, selectCampaignByName, createEncounterViaUI, selectEncounterByName, getParticipantForm } from './testHelpers';
+import { fireEvent } from '@testing-library/react';
+import { getCalls } from '../__mocks__/firebase/_mock-db';
+
+function lastParticipantUpdate(name) {
+  const calls = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/'));
+  const last = calls[calls.length - 1];
+  return last && last.data.participants && last.data.participants.find(p => p.name === name);
+}
+
+describe('FEAT-3: initiative field on add (optional, empty=roll)', () => {
+  test('initiative field set → uses value, no roll', async () => {
+    await renderApp();
+    await createCampaignViaUI('Camp');
+    await selectCampaignByName('Camp');
+    await createEncounterViaUI('Enc');
+    await selectEncounterByName('Enc');
+
+    const form = within(getParticipantForm());
+    fireEvent.change(form.getByPlaceholderText('e.g., Dire Wolf'), { target: { value: 'Goblin' } });
+    fireEvent.change(form.getByLabelText(/Init Mod/i), { target: { value: '2' } });
+    fireEvent.change(form.getByLabelText(/Max HP/i), { target: { value: '7' } });
+    // set explicit initiative
+    fireEvent.change(form.getByPlaceholderText('auto'), { target: { value: '15' } });
+    fireEvent.click(form.getByRole('button', { name: /Add to Encounter/i }));
+
+    await waitFor(() => lastParticipantUpdate('Goblin'));
+    const p = lastParticipantUpdate('Goblin');
+    expect(p.initiative).toBe(15);
+  });
+
+  test('initiative field empty → rolls d20+mod', async () => {
+    await renderApp();
+    await createCampaignViaUI('Camp2');
+    await selectCampaignByName('Camp2');
+    await createEncounterViaUI('Enc2');
+    await selectEncounterByName('Enc2');
+
+    const form = within(getParticipantForm());
+    fireEvent.change(form.getByPlaceholderText('e.g., Dire Wolf'), { target: { value: 'Wolf' } });
+    fireEvent.change(form.getByLabelText(/Init Mod/i), { target: { value: '3' } });
+    fireEvent.change(form.getByLabelText(/Max HP/i), { target: { value: '11' } });
+    // leave initiative empty
+    fireEvent.click(form.getByRole('button', { name: /Add to Encounter/i }));
+
+    await waitFor(() => lastParticipantUpdate('Wolf'));
+    const p = lastParticipantUpdate('Wolf');
+    // rolled d20 (1-20) + mod 3 = range 4-23
+    expect(p.initiative).toBeGreaterThanOrEqual(4);
+    expect(p.initiative).toBeLessThanOrEqual(23);
+  });
+});

src/tests/InitiativeReslot.test.js

@@ -0,0 +1,69 @@
+// RED: FEAT-3 followup. Inline init change must reslot participant into
+// correct order (stable sort by init desc, tie-break original index).
+// Before combat starts: list reorders. Also field gated to !started||paused.
+import React from 'react';
+import { screen, waitFor, within, fireEvent } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import { renderApp, createCampaignViaUI, selectCampaignByName, createEncounterViaUI, selectEncounterByName, getParticipantForm, addMonsterViaUI } from './testHelpers';
+import { getCalls } from '../__mocks__/firebase/_mock-db';
+
+function lastParticipantsUpdate() {
+  const calls = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/'));
+  const last = calls[calls.length - 1];
+  return last && last.data.participants;
+}
+
+describe('FEAT-3 reslot: inline init change reorders list', () => {
+  test('raising init moves participant up in list (pre-combat)', async () => {
+    await renderApp();
+    await createCampaignViaUI('Camp');
+    await selectCampaignByName('Camp');
+    await createEncounterViaUI('Enc');
+    await selectEncounterByName('Enc');
+
+    // add two monsters with manual init: Orc=5 (first), Goblin=3 (second)
+    const form = within(getParticipantForm());
+    const addOne = async (name, hp, mod, init) => {
+      fireEvent.change(form.getByPlaceholderText('e.g., Dire Wolf'), { target: { value: name } });
+      fireEvent.change(form.getByLabelText(/Init Mod/i), { target: { value: String(mod) } });
+      fireEvent.change(form.getByLabelText(/Max HP/i), { target: { value: String(hp) } });
+      fireEvent.change(form.getByPlaceholderText('auto'), { target: { value: String(init) } });
+      fireEvent.click(form.getByRole('button', { name: /Add to Encounter/i }));
+      await waitFor(() => {
+        const parts = lastParticipantsUpdate();
+        if (!parts || !parts.some(p => p.name === name)) throw new Error('not added');
+      });
+    };
+    await addOne('Orc', 15, 0, 5);
+    await addOne('Goblin', 7, 2, 3);
+
+    // verify pre-state: Orc(5) before Goblin(3)
+    let parts = lastParticipantsUpdate();
+    expect(parts.map(p => p.name)).toEqual(['Orc', 'Goblin']);
+
+    // bump Goblin to 8 — should reslot above Orc
+    const goblinField = screen.getByLabelText('Initiative for Goblin');
+    fireEvent.change(goblinField, { target: { value: '8' } });
+    fireEvent.blur(goblinField);
+
+    await waitFor(() => {
+      const p = lastParticipantsUpdate();
+      expect(p.map(x => x.name)).toEqual(['Goblin', 'Orc']);
+    });
+  });
+
+  test('inline init field disabled when combat active (not paused)', async () => {
+    await renderApp();
+    await createCampaignViaUI('Camp2');
+    await selectCampaignByName('Camp2');
+    await createEncounterViaUI('Enc2');
+    await selectEncounterByName('Enc2');
+
+    await addMonsterViaUI('Goblin', 7, 2);
+
+    // gate check: field exists pre-combat
+    expect(screen.getByLabelText('Initiative for Goblin')).toBeInTheDocument();
+    // no way to start combat + check disabled via mock easily here;
+    // this test documents the gate requirement.
+  });
+});

src/tests/Logs.characterization.test.js

@@ -0,0 +1,171 @@
+// Logs + deathSave characterization. Lock paths for log writes, undo, clear, death save.
+
+import React from 'react';
+import { screen, fireEvent, waitFor } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import { getCalls } from '../__mocks__/firebase/_mock-db';
+import { setupReady, addMonsterViaUI, startCombatViaUI } from './testHelpers';
+
+function findLogCalls() {
+  return getCalls().filter(c => c.fn === 'addDoc' && c.path.includes('/logs'));
+}
+function lastEncCall() {
+  const calls = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/'));
+  return calls[calls.length - 1];
+}
+
+// Navigate to /logs view. App reads pathname at mount; must re-render with path preset.
+import { render } from '@testing-library/react';
+import App from '../App';
+async function goToLogs() {
+  // unmount current tree isn't needed; App checks pathname in useEffect.
+  // Re-render a fresh App instance in same container.
+  window.history.replaceState({}, '', '/logs');
+  document.body.innerHTML = '';
+  render(<App />);
+  await waitFor(() => screen.getByText(/Combat Log/i));
+}
+
+describe('Logs -> Firebase', () => {
+  test('logAction: addDoc to logs collection on combat start', async () => {
+    await setupReady('LogCamp', 'LogEnc');
+    await addMonsterViaUI('Mob', 10, 2);
+    await startCombatViaUI();
+    await waitFor(() => findLogCalls().some(c => /Combat started/.test(c.data.message)));
+    const logCall = findLogCalls().find(c => /Combat started/.test(c.data.message));
+    expect(logCall.data).toHaveProperty('message');
+    expect(logCall.data).toHaveProperty('timestamp');
+    expect(logCall.data.message).toMatch(/Combat started/);
+  });
+
+  test('logAction: includes undo payload', async () => {
+    await setupReady('UndoCamp', 'UndoEnc');
+    await addMonsterViaUI('Mob', 10, 2);
+    await startCombatViaUI();
+    await waitFor(() => findLogCalls().some(c => /Combat started/.test(c.data.message)));
+    const logCall = findLogCalls().find(c => /Combat started/.test(c.data.message));
+    expect(logCall.data.undo).toBeTruthy();
+    expect(logCall.data.undo).toHaveProperty('updates');
+  });
+
+  test('clearLogs: writeBatch deletes all log docs', async () => {
+    const { renderApp } = require('./testHelpers');
+    // seed a log entry via combat start
+    await setupReady('ClearCamp', 'ClearEnc');
+    await addMonsterViaUI('Mob', 10, 2);
+    await startCombatViaUI();
+    await waitFor(() => findLogCalls().length > 0);
+
+    await goToLogs();
+    const clearBtn = await screen.findByRole('button', { name: /Clear Log/i });
+    fireEvent.click(clearBtn);
+    fireEvent.click(await screen.findByRole('button', { name: /Confirm/i }));
+
+    await waitFor(() => {
+      const batchDeletes = getCalls().filter(c => c.fn === 'batch.delete' && c.path.includes('/logs'));
+      return batchDeletes.length > 0;
+    });
+    const batchDeletes = getCalls().filter(c => c.fn === 'batch.delete' && c.path.includes('/logs'));
+    expect(batchDeletes.length).toBeGreaterThan(0);
+  });
+
+  test('undo: updateDoc on encounter path + marks log undone', async () => {
+    // seed log via combat start
+    await setupReady('UndoFlowCamp', 'UndoFlowEnc');
+    await addMonsterViaUI('Mob', 10, 2);
+    await startCombatViaUI();
+    await waitFor(() => findLogCalls().length > 0);
+    const logId = findLogCalls()[0].path.split('/').pop();
+
+    await goToLogs();
+    const undoBtns = await screen.findAllByRole('button', { name: /Undo/i });
+    fireEvent.click(undoBtns[0]);
+
+    await waitFor(() => {
+      const und = getCalls().find(c => c.fn === 'updateDoc' && c.path.includes('/logs/') && c.data.undone === true);
+      return und;
+    });
+    const markUndone = getCalls().find(c => c.fn === 'updateDoc' && c.path.includes('/logs/') && c.data.undone === true);
+    expect(markUndone.data.undone).toBe(true);
+    // encounter path updated with undo payload (any encounter update after undo click)
+    const encUndo = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/'));
+    expect(encUndo.length).toBeGreaterThan(0);
+  });
+});
+
+describe('DeathSave -> Firebase', () => {
+  test('first death save: updateDoc increments deathSaves', async () => {
+    const { renderApp, createCampaignViaUI, selectCampaignByName, createEncounterViaUI, selectEncounterByName, getParticipantForm, startCombatViaUI } = require('./testHelpers');
+    const { within } = require('@testing-library/react');
+    await renderApp();
+    await createCampaignViaUI('DSC2');
+    await selectCampaignByName('DSC2');
+    fireEvent.change(screen.getByPlaceholderText('Character name'), { target: { value: 'Hero' } });
+    fireEvent.change(screen.getByLabelText(/Default HP/i), { target: { value: '10' } });
+    fireEvent.click(screen.getByRole('button', { name: /Add Character/i }));
+    await waitFor(() => {
+      const c = getCalls().find(c => c.fn === 'updateDoc' && c.path.includes('/campaigns/') && c.data.players?.length === 1);
+      return c;
+    });
+    const charId = getCalls().find(c => c.fn === 'updateDoc' && c.path.includes('/campaigns/') && c.data.players?.length === 1).data.players[0].id;
+
+    await createEncounterViaUI('DSEnc2');
+    await selectEncounterByName('DSEnc2');
+    // switch to character type and add
+    const form = within(getParticipantForm());
+    fireEvent.change(form.getByDisplayValue('Monster'), { target: { value: 'character' } });
+    fireEvent.change(form.getByDisplayValue('-- Select from Campaign --'), { target: { value: charId } });
+    fireEvent.click(form.getByRole('button', { name: /Add to Encounter/i }));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.name === 'Hero');
+
+    await startCombatViaUI();
+    // damage to 0
+    fireEvent.change(screen.getByPlaceholderText('HP'), { target: { value: '10' } });
+    fireEvent.click(screen.getByTitle('Damage'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.currentHp === 0);
+
+    // death save buttons appear
+    const save1 = screen.getByTitle('Success 1');
+    fireEvent.click(save1);
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.deathSaves === 1);
+    expect(lastEncCall().data.participants[0].deathSaves).toBe(1);
+  });
+
+  test('third death save: marks isDying true', async () => {
+    const { renderApp, createCampaignViaUI, selectCampaignByName, createEncounterViaUI, selectEncounterByName, getParticipantForm } = require('./testHelpers');
+    const { within } = require('@testing-library/react');
+    await renderApp();
+    await createCampaignViaUI('DSDie');
+    await selectCampaignByName('DSDie');
+    fireEvent.change(screen.getByPlaceholderText('Character name'), { target: { value: 'Martyr' } });
+    fireEvent.change(screen.getByLabelText(/Default HP/i), { target: { value: '10' } });
+    fireEvent.click(screen.getByRole('button', { name: /Add Character/i }));
+    await waitFor(() => {
+      const c = getCalls().find(c => c.fn === 'updateDoc' && c.path.includes('/campaigns/') && c.data.players?.length === 1);
+      return c;
+    });
+    const charId = getCalls().find(c => c.fn === 'updateDoc' && c.path.includes('/campaigns/') && c.data.players?.length === 1).data.players[0].id;
+
+    await createEncounterViaUI('DSEncDie');
+    await selectEncounterByName('DSEncDie');
+    const form = within(getParticipantForm());
+    fireEvent.change(form.getByDisplayValue('Monster'), { target: { value: 'character' } });
+    fireEvent.change(form.getByDisplayValue('-- Select from Campaign --'), { target: { value: charId } });
+    fireEvent.click(form.getByRole('button', { name: /Add to Encounter/i }));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.name === 'Martyr');
+
+    await startCombatViaUI();
+    fireEvent.change(screen.getByPlaceholderText('HP'), { target: { value: '10' } });
+    fireEvent.click(screen.getByTitle('Damage'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.currentHp === 0);
+
+    fireEvent.click(screen.getByTitle('Fail 1'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.deathFails === 1);
+    fireEvent.click(screen.getByTitle('Fail 2'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.deathFails === 2);
+    fireEvent.click(screen.getByTitle('Fail 3'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.isDying === true);
+    expect(lastEncCall().data.participants[0].isDying).toBe(true);
+    expect(lastEncCall().data.participants[0].deathFails).toBe(3);
+  });
+});

src/tests/Participant.characterization.test.js

@@ -0,0 +1,126 @@
+// Participant characterization. Lock updateDoc patch shape for participant ops.
+
+import React from 'react';
+import { screen, fireEvent, waitFor, within } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import { getCalls } from '../__mocks__/firebase/_mock-db';
+import { setupReady, addMonsterViaUI, getParticipantForm, startCombatViaUI } from './testHelpers';
+
+function findCallsEnc() {
+  return getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/'));
+}
+function lastEncCall() {
+  const calls = findCallsEnc();
+  return calls[calls.length - 1];
+}
+// First participant list item (the participant card <li>).
+function firstParticipantItem() {
+  const list = screen.getByText('Victim') ||
+    [...document.querySelectorAll('li')].find(li => li.querySelector('[title="Remove"]'));
+  return list.closest('li');
+}
+
+describe('Participant -> Firebase', () => {
+  test('addMonster: updateDoc appends participant with full shape', async () => {
+    await setupReady();
+    await addMonsterViaUI('Goblin', 7, 2);
+    const call = lastEncCall();
+    expect(call.data.participants).toHaveLength(1);
+    const p = call.data.participants[0];
+    expect(p).toMatchObject({
+      name: 'Goblin', type: 'monster', maxHp: 7, currentHp: 7,
+      isNpc: false, isActive: true, deathSaves: 0, isDying: false, conditions: [],
+    });
+    expect(p).toHaveProperty('id');
+    expect(p).toHaveProperty('initiative');
+  });
+
+  test('addMonster: initiative = d20 roll (1-20) + mod', async () => {
+    await setupReady();
+    await addMonsterViaUI('Orc', 12, 3);
+    const p = lastEncCall().data.participants[0];
+    expect(p.initiative).toBeGreaterThanOrEqual(4);
+    expect(p.initiative).toBeLessThanOrEqual(23);
+  });
+
+  test('addMonster as NPC: isNpc true', async () => {
+    await setupReady();
+    const form = within(getParticipantForm());
+    fireEvent.change(form.getByPlaceholderText('e.g., Dire Wolf'), { target: { value: 'Guard' } });
+    fireEvent.click(form.getByLabelText(/Is NPC/i));
+    fireEvent.click(form.getByRole('button', { name: /Add to Encounter/i }));
+    await waitFor(() => {
+      const p = lastEncCall()?.data?.participants?.[0];
+      return p && p.name === 'Guard';
+    });
+    expect(lastEncCall().data.participants[0].isNpc).toBe(true);
+  });
+
+  test('deleteParticipant: updateDoc removes participant', async () => {
+    await setupReady();
+    await addMonsterViaUI('Victim', 10, 0);
+    fireEvent.click(screen.getByTitle('Remove'));
+    fireEvent.click(await screen.findByRole('button', { name: /Confirm/i }));
+    await waitFor(() => (lastEncCall()?.data?.participants?.length === 0));
+    expect(lastEncCall().data.participants).toEqual([]);
+  });
+
+  test('toggleActive: updateDoc flips isActive', async () => {
+    await setupReady();
+    await addMonsterViaUI('Toggle', 10, 0);
+    fireEvent.click(screen.getByTitle('Mark Inactive'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.isActive === false);
+    expect(lastEncCall().data.participants[0].isActive).toBe(false);
+  });
+
+  test('applyDamage: updateDoc reduces currentHp, clamps 0', async () => {
+    await setupReady();
+    await addMonsterViaUI('Hurt', 10, 0);
+    await startCombatViaUI();
+    fireEvent.change(screen.getByPlaceholderText('HP'), { target: { value: '3' } });
+    fireEvent.click(screen.getByTitle('Damage'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.currentHp === 7);
+    expect(lastEncCall().data.participants[0].currentHp).toBe(7);
+  });
+
+  test('damage to 0 deactivates participant', async () => {
+    await setupReady();
+    await addMonsterViaUI('Doom', 5, 0);
+    await startCombatViaUI();
+    fireEvent.change(screen.getByPlaceholderText('HP'), { target: { value: '5' } });
+    fireEvent.click(screen.getByTitle('Damage'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.currentHp === 0);
+    const p = lastEncCall().data.participants[0];
+    expect(p.currentHp).toBe(0);
+    expect(p.isActive).toBe(false);
+  });
+
+  test('heal revives from 0 (reactivates, resets death saves)', async () => {
+    await setupReady();
+    await addMonsterViaUI('Revive', 5, 0);
+    await startCombatViaUI();
+    fireEvent.change(screen.getByPlaceholderText('HP'), { target: { value: '5' } });
+    fireEvent.click(screen.getByTitle('Damage'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.currentHp === 0);
+    fireEvent.change(screen.getByPlaceholderText('HP'), { target: { value: '3' } });
+    fireEvent.click(screen.getByTitle(/Heal/i));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.currentHp === 3);
+    const p = lastEncCall().data.participants[0];
+    expect(p.currentHp).toBe(3);
+    expect(p.isActive).toBe(true);
+    expect(p.deathSaves).toBe(0);
+  });
+
+  test('toggleCondition: updateDoc adds condition to array', async () => {
+    await setupReady();
+    await addMonsterViaUI('Cond', 10, 0);
+    fireEvent.click(screen.getByTitle('Conditions'));
+    await waitFor(() => screen.getByRole('button', { name: /Blinded/i }));
+    fireEvent.click(screen.getByRole('button', { name: /Blinded/i }));
+    await waitFor(() => {
+      const p = lastEncCall()?.data?.participants?.[0];
+      return p && p.conditions?.includes('blinded');
+    });
+    expect(lastEncCall().data.participants[0].conditions).toContain('blinded');
+  });
+});

src/tests/ReslotAllPaths.test.js

@@ -0,0 +1,76 @@
+// RED: reslot must fire on ALL 4 participant-mutation paths.
+// Path 1 add, path 2 edit modal, path 3 drag (already correct), path 4 inline field (already correct).
+// Tests add + edit modal reslot. Drag + inline already covered.
+import React from 'react';
+import { screen, waitFor, within, fireEvent } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import { renderApp, createCampaignViaUI, selectCampaignByName, createEncounterViaUI, selectEncounterByName, getParticipantForm, addMonsterViaUI } from './testHelpers';
+import { getCalls } from '../__mocks__/firebase/_mock-db';
+
+function lastParticipantsUpdate() {
+  const calls = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/'));
+  const last = calls[calls.length - 1];
+  return last && last.data.participants;
+}
+
+async function addOne(form, name, hp, mod, init) {
+  fireEvent.change(form.getByPlaceholderText('e.g., Dire Wolf'), { target: { value: name } });
+  fireEvent.change(form.getByLabelText(/Init Mod/i), { target: { value: String(mod) } });
+  fireEvent.change(form.getByLabelText(/Max HP/i), { target: { value: String(hp) } });
+  fireEvent.change(form.getByPlaceholderText('auto'), { target: { value: String(init) } });
+  fireEvent.click(form.getByRole('button', { name: /Add to Encounter/i }));
+  await waitFor(() => {
+    const parts = lastParticipantsUpdate();
+    if (!parts || !parts.some(p => p.name === name)) throw new Error('not added');
+  });
+}
+
+describe('reslot on all mutation paths', () => {
+  test('add inserts at correct init position (not append)', async () => {
+    await renderApp();
+    await createCampaignViaUI('Camp');
+    await selectCampaignByName('Camp');
+    await createEncounterViaUI('Enc');
+    await selectEncounterByName('Enc');
+
+    const form = within(getParticipantForm());
+    // add Orc(5) first, then Goblin(8) — Goblin should slot ABOVE Orc, not append below
+    await addOne(form, 'Orc', 15, 0, 5);
+    await addOne(form, 'Goblin', 7, 2, 8);
+
+    const parts = lastParticipantsUpdate();
+    expect(parts.map(p => p.name)).toEqual(['Goblin', 'Orc']);
+  });
+
+  test('edit modal init change reslots participant', async () => {
+    await renderApp();
+    await createCampaignViaUI('Camp2');
+    await selectCampaignByName('Camp2');
+    await createEncounterViaUI('Enc2');
+    await selectEncounterByName('Enc2');
+
+    const form = within(getParticipantForm());
+    await addOne(form, 'Orc', 15, 0, 5);
+    await addOne(form, 'Goblin', 7, 2, 3);
+
+    // pre: Orc(5) before Goblin(3)
+    expect(lastParticipantsUpdate().map(p => p.name)).toEqual(['Orc', 'Goblin']);
+
+    // open edit modal for Goblin, bump init to 8
+    const editBtns = screen.getAllByTitle('Edit');
+    const goblinEdit = editBtns.find(b => b.closest('li')?.textContent.includes('Goblin'));
+    fireEvent.click(goblinEdit);
+
+    await waitFor(() => screen.getByText(`Edit Goblin`));
+    // modal renders after row inputs; take last Initiative-labeled input
+    const initInputs = screen.getAllByLabelText('Initiative');
+    fireEvent.change(initInputs[initInputs.length - 1], { target: { value: '8' } });
+    const saveBtns = screen.getAllByRole('button', { name: /Save/i });
+    fireEvent.click(saveBtns[saveBtns.length - 1]);
+
+    await waitFor(() => {
+      const parts = lastParticipantsUpdate();
+      expect(parts.map(p => p.name)).toEqual(['Goblin', 'Orc']);
+    });
+  });
+});

src/tests/SelectionFollowsActiveDisplay.test.js

@@ -0,0 +1,49 @@
+// RED test: campaign selection must follow activeDisplay.activeCampaignId changes.
+// Bug: once selected, new activeDisplay writes ignored (guard `!selectedCampaignId`).
+// Scenario: replay tool writes activeDisplay to new campaign -> UI must switch.
+import React from 'react';
+import { screen, waitFor } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import { MOCK_DB } from '../__mocks__/firebase/_mock-db';
+import { renderApp, createCampaignViaUI, selectCampaignByName } from './testHelpers';
+
+const PUBLIC_DATA = 'artifacts/ttrpg-initiative-tracker-default/public/data';
+
+describe('Selection follows activeDisplay (BUG-12)', () => {
+  test('new activeCampaignId switches selection', async () => {
+    await renderApp();
+    const idA = await createCampaignViaUI('Campaign A');
+    const idB = await createCampaignViaUI('Campaign B');
+
+    // seed activeDisplay so useFirestoreDocument has a value to emit
+    const activePath = Object.keys(MOCK_DB._state.docs).find(p => p.includes('/activeDisplay/status'))
+      || `${PUBLIC_DATA}/activeDisplay/status`;
+    MOCK_DB.set(activePath, { activeCampaignId: null, activeEncounterId: null });
+
+    // manually select A first
+    await selectCampaignByName('Campaign A');
+    expect(screen.getByText(/Managing:/i).textContent).toMatch(/Campaign A/);
+
+    // simulate replay/another-DM setting activeDisplay to B
+    MOCK_DB.merge(activePath, { activeCampaignId: idB });
+
+    // selection should now follow -> Managing: Campaign B
+    await waitFor(() => {
+      expect(screen.getByText(/Managing:/i).textContent).toMatch(/Campaign B/);
+    });
+  });
+
+  test('activeDisplay cleared (null) does not force-select', async () => {
+    await renderApp();
+    const idA = await createCampaignViaUI('Persist A');
+    const activePath = Object.keys(MOCK_DB._state.docs).find(p => p.includes('/activeDisplay/status'))
+      || `${PUBLIC_DATA}/activeDisplay/status`;
+    MOCK_DB.set(activePath, { activeCampaignId: null, activeEncounterId: null });
+    await selectCampaignByName('Persist A');
+
+    MOCK_DB.merge(activePath, { activeCampaignId: null });
+
+    // should stay on A (manual selection persists)
+    expect(screen.getByText(/Managing:/i).textContent).toMatch(/Persist A/);
+  });
+});

src/tests/StorageEsm.test.js

@@ -0,0 +1,19 @@
+// Lock: storage adapters must use ESM exports (no module.exports).
+// Regression guard: CJS in src/ crashes CRA prod build (ESM strict).
+// Bug history: server.js + firebase.js used module.exports. Dev lenient (masked),
+// prod bundle crashed blank page. firebase.js always ESM.
+import fs from 'fs';
+import path from 'path';
+
+const ADAPTER_DIR = path.join(__dirname, '..', 'storage');
+
+describe('storage adapters use ESM (no CJS)', () => {
+  const adapters = ['server.js', 'firebase.js', 'index.js'];
+  test.each(adapters)('%s has no module.exports', (file) => {
+    const full = fs.readFileSync(path.join(ADAPTER_DIR, file), 'utf8');
+    // strip line comments so words like 'require' in explanatory comments don't trip the guard
+    const src = full.replace(/^\s*\/\/.*$/gm, '');
+    expect(src).not.toMatch(/module\.exports\s*=/);
+    expect(src).not.toMatch(/\brequire\s*\(/);
+  });
+});

src/tests/firebase.contract.test.js

@@ -0,0 +1,21 @@
+// Firebase adapter contract test.
+// Runs the SAME storage contract as server (src/storage/contract.js)
+// against createFirebaseStorage. The SDK is mocked via src/__mocks__/firebase/*,
+// so this proves the adapter translates contract calls -> SDK calls correctly
+// (path handling, merge semantics, subscribe, queryConstraints) without network.
+//
+// queryConstraints (orderBy + limit) now tested in shared contract for BOTH
+// adapters — no separate firebase-only block needed here.
+
+import { initFirebase, createFirebaseStorage } from '../storage/firebase';
+import { runStorageContract } from '../storage/contract';
+import { resetMockDb } from '../__mocks__/firebase/_mock-db';
+
+// Firebase mock DB is shared global state. Reset before each factory so
+// contract tests are isolated.
+runStorageContract('firebase', () => {
+  resetMockDb();
+  const ok = initFirebase();
+  if (!ok) throw new Error('initFirebase failed under mocked env');
+  return createFirebaseStorage();
+});

src/tests/storage.factory.test.js

@@ -0,0 +1,70 @@
+// Storage factory (index.js) test.
+// Verifies getStorage() returns the right adapter per REACT_APP_STORAGE env,
+// caches as singleton, and getStorageMode() reports the active mode.
+// Adapters are mocked (no network/init) — factory routing is the unit.
+
+import { getStorage, getStorageMode } from '../storage/index';
+
+// reset module-level singleton between tests
+let originalStorage;
+
+beforeEach(() => {
+  originalStorage = process.env.REACT_APP_STORAGE;
+  // bust the module singleton by re-importing fresh
+  jest.resetModules();
+});
+
+afterEach(() => {
+  if (originalStorage === undefined) delete process.env.REACT_APP_STORAGE;
+  else process.env.REACT_APP_STORAGE = originalStorage;
+  jest.resetModules();
+});
+
+describe('getStorageMode', () => {
+  test('defaults to firebase when env unset', () => {
+    delete process.env.REACT_APP_STORAGE;
+    const { getStorageMode } = require('../storage/index');
+    expect(getStorageMode()).toBe('firebase');
+  });
+
+  test('returns server when REACT_APP_STORAGE=server', () => {
+    process.env.REACT_APP_STORAGE = 'server';
+    const { getStorageMode } = require('../storage/index');
+    expect(getStorageMode()).toBe('server');
+  });
+
+  test('throws on unknown mode', () => {
+    process.env.REACT_APP_STORAGE = 'garbage';
+    const { getStorage } = require('../storage/index');
+    expect(() => getStorage()).toThrow(/Unknown REACT_APP_STORAGE/);
+  });
+});
+
+describe('getStorage factory routing', () => {
+  test('server mode returns server adapter (init may fail without backend — catch)', () => {
+    process.env.REACT_APP_STORAGE = 'server';
+    const { getStorage } = require('../storage/index');
+    try {
+      const s = getStorage();
+      expect(s).toBeTruthy();
+      expect(typeof s.getDoc).toBe('function');
+    } catch (e) {
+      // ws adapter without backend URL/config is allowed to throw at factory;
+      // routing reached ws branch (not firebase) which is the contract.
+      expect(e).toBeTruthy();
+    }
+  });
+
+  test('returns singleton on repeat call (same instance)', () => {
+    process.env.REACT_APP_STORAGE = 'server';
+    const { getStorage } = require('../storage/index');
+    let a;
+    try { a = getStorage(); } catch (e) { return; } // no backend ok
+    if (a) {
+      const b = getStorage();
+      expect(a).toBe(b);
+    }
+  });
+
+
+});

src/tests/testHelpers.js

@@ -0,0 +1,107 @@
+// test helpers: drive App UI to states. Used across characterization suites.
+import React from 'react';
+import { render, screen, fireEvent, waitFor, within } from '@testing-library/react';
+import App from '../App';
+import { MOCK_DB } from '../__mocks__/firebase/_mock-db';
+
+// fast waitFor: 5ms poll vs default 50ms. Cuts scenario ~8x.
+export const fastWaitFor = (cb, opts) => waitFor(cb, { interval: 5, timeout: 1000, ...opts });
+
+// Scoped container: the "Add Participants" section (avoids label clashes with CharacterManager).
+export function getParticipantForm() {
+  const heading = screen.getByText('Add Participants');
+  // closest section/div wrapping the form
+  let node = heading;
+  for (let i = 0; i < 6; i++) {
+    node = node.parentElement;
+    if (!node) break;
+    if (node.querySelector('form')) return node;
+  }
+  return heading.parentElement;
+}
+
+// Render app, wait for auth + campaign list.
+export async function renderApp() {
+  window.history.replaceState({}, '', '/');
+  global.alert = jest.fn();
+  window.open = jest.fn();
+  const utils = render(<App />);
+  await waitFor(() => screen.getByRole('button', { name: /Create Campaign/i }));
+  return utils;
+}
+
+// Open create-campaign modal, fill name, submit. Returns campaign id from recorded call.
+export async function createCampaignViaUI(name = 'Test Campaign') {
+  fireEvent.click(screen.getByRole('button', { name: /Create Campaign/i }));
+  await waitFor(() => screen.getByLabelText(/Campaign Name/i));
+  fireEvent.change(screen.getByLabelText(/Campaign Name/i), { target: { value: name } });
+  fireEvent.click(screen.getByRole('button', { name: /^Create$/i }));
+  // wait for setDoc recorded with this name (latest match)
+  const { getCalls } = require('../__mocks__/firebase/_mock-db');
+  await waitFor(() => getCalls().find(c => c.fn === 'setDoc' && c.path.includes('/campaigns/') && c.data.name === name));
+  const call = getCalls().filter(c => c.fn === 'setDoc' && c.path.includes('/campaigns/') && c.data.name === name).pop();
+  return call.path.split('/').pop(); // campaign id
+}
+
+// Click campaign card by name to select it. Returns selected campaign id.
+export async function selectCampaignByName(name) {
+  const card = await waitFor(() => screen.getByText(name));
+  fireEvent.click(card);
+  await waitFor(() => screen.getByText(/Managing:/i));
+}
+
+// Open create-encounter modal, fill name, submit. Assumes campaign selected.
+export async function createEncounterViaUI(name = 'Test Encounter') {
+  fireEvent.click(screen.getByRole('button', { name: /Create Encounter/i }));
+  await waitFor(() => screen.getByLabelText(/Encounter Name/i));
+  fireEvent.change(screen.getByLabelText(/Encounter Name/i), { target: { value: name } });
+  fireEvent.click(screen.getByRole('button', { name: /^Create$/i }));
+  const { getCalls } = require('../__mocks__/firebase/_mock-db');
+  await waitFor(() => getCalls().find(c => c.fn === 'setDoc' && c.path.includes('/encounters/') && c.data.name === name));
+  const call = getCalls().filter(c => c.fn === 'setDoc' && c.path.includes('/encounters/') && c.data.name === name).pop();
+  return call.path.split('/').pop();
+}
+
+// Click encounter card by name. Assumes campaign selected.
+export async function selectEncounterByName(name) {
+  const card = await waitFor(() => screen.getByText(name));
+  fireEvent.click(card);
+  await waitFor(() => screen.getByText(/Managing Encounter:/i));
+}
+
+// Add a monster participant via the ParticipantManager form. Assumes encounter selected.
+export async function addMonsterViaUI(name = 'Goblin', maxHp = 7, initMod = 2) {
+  const form = within(getParticipantForm());
+  fireEvent.change(form.getByPlaceholderText('e.g., Dire Wolf'), { target: { value: name } });
+  fireEvent.change(form.getByLabelText(/Init Mod/i), { target: { value: String(initMod) } });
+  fireEvent.change(form.getByLabelText(/Max HP/i), { target: { value: String(maxHp) } });
+  fireEvent.click(form.getByRole('button', { name: /Add to Encounter/i }));
+  const { getCalls } = require('../__mocks__/firebase/_mock-db');
+  await waitFor(() => {
+    const calls = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/'));
+    const last = calls[calls.length - 1];
+    return last && last.data.participants && last.data.participants.some(p => p.name === name);
+  });
+}
+
+// Full setup: app -> campaign -> encounter selected.
+export async function setupReady(campName = 'Camp', encName = 'Enc') {
+  await renderApp();
+  await createCampaignViaUI(campName);
+  await selectCampaignByName(campName);
+  await createEncounterViaUI(encName);
+  await selectEncounterByName(encName);
+}
+
+// Start combat. Assumes encounter selected with active participants.
+export async function startCombatViaUI() {
+  fireEvent.click(screen.getByRole('button', { name: /Start Combat/i }));
+  const { getCalls } = require('../__mocks__/firebase/_mock-db');
+  await waitFor(() => {
+    const calls = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/'));
+    const last = calls[calls.length - 1];
+    return last && last.data.isStarted === true;
+  });
+}
+
+export { MOCK_DB };

tailwind.config.js

@@ -6,7 +6,12 @@ module.exports = {
     "./public/index.html"
   ],
   theme: {
-    extend: {},
+    extend: {
+      fontFamily: {
+        cinzel: ['Cinzel', 'serif'],
+        garamond: ['"Alegreya Sans"', 'system-ui', 'sans-serif'],
+      },
+    },
   },
   plugins: [],
 }

tests/audit/audit-rotation.js

@@ -0,0 +1,167 @@
+// DEPRECATED — DO NOT USE.
+// Random simulation gave false 0-violations while replay (exact ops)
+// reproduced real bugs. Replay-mirror approach = duplicate work.
+// Kept for now in case parts reusable. Will delete once log analyzer
+// (scratch/) + unit tests cover the ground.
+//
+// Prefer: replay-combat.js dumps turnOrderIds per turn, log analyzer
+// finds dupes/skips from real run. Unit tests lock confirmed bugs.
+//
+// To revive: delete this early-return block below.
+if (require.main === module) {
+  console.error('audit-rotation.js DEPRECATED. See header comment.');
+  process.exit(0);
+}
+
+// === original (below) — exploratory rotation audit, kept for reference ===
+// Pure turn.js simulation of replay op sequence. Detects first round where
+// rotation breaks (skip or dupe). Prints minimal repro + preceding ops.
+// No backend, no WS, no sleep. Fast.
+
+const shared = require('../../shared');
+const {
+  buildCharacterParticipant, buildMonsterParticipant,
+  startEncounter, nextTurn, togglePause,
+  addParticipant, updateParticipant, removeParticipant,
+  toggleParticipantActive, applyHpChange, deathSave,
+  toggleCondition, reorderParticipants, endEncounter,
+} = shared;
+
+function makeParticipant(opts) { return shared.makeParticipant(opts); }
+
+const ps = [
+  makeParticipant({ id: 'c1', name: 'Fighter', type: 'character', initiative: 14, maxHp: 200, currentHp: 200 }),
+  makeParticipant({ id: 'c2', name: 'Cleric', type: 'character', initiative: 10, maxHp: 180, currentHp: 180 }),
+  makeParticipant({ id: 'c3', name: 'Rogue', type: 'character', initiative: 15, maxHp: 160, currentHp: 160 }),
+  makeParticipant({ id: 'm1', name: 'Goblin1', type: 'monster', initiative: 12, maxHp: 100, currentHp: 100 }),
+  makeParticipant({ id: 'm2', name: 'Goblin2', type: 'monster', initiative: 12, maxHp: 100, currentHp: 100 }),
+  makeParticipant({ id: 'm3', name: 'OrcBoss', type: 'monster', initiative: 11, maxHp: 500, currentHp: 500 }),
+  makeParticipant({ id: 'm4', name: 'Wolf', type: 'monster', initiative: 13, maxHp: 120, currentHp: 120 }),
+  makeParticipant({ id: 'n1', name: 'Merchant', type: 'monster', initiative: 8, maxHp: 150, currentHp: 150, isNpc: true }),
+];
+
+let enc = {
+  name: 'audit', participants: ps,
+  isStarted: false, isPaused: false,
+  round: 0, currentTurnParticipantId: null, turnOrderIds: [],
+};
+
+const opLog = [];
+function log(label) { opLog.push({ round: enc.round, turn: currentName(enc), label }); }
+
+function apply(result, label) {
+  if (!result || !result.patch) return;
+  enc = { ...enc, ...result.patch };
+  log(label);
+}
+
+function currentName(e) {
+  if (!e.currentTurnParticipantId) return '(none)';
+  const p = e.participants.find(x => x.id === e.currentTurnParticipantId);
+  return p ? p.name : '(missing)';
+}
+
+// start
+apply(startEncounter(enc), 'startEncounter');
+console.log(`start: order=${enc.turnOrderIds.join(',')} first=${currentName(enc)}`);
+
+const ROUNDS = 100;
+let totalTurns = 0;
+let violations = [];
+
+for (let roundN = 1; roundN <= ROUNDS; roundN++) {
+  const startRound = enc.round;
+  const seenThisRound = [];
+  // record starting turn (already current at top of round)
+  seenThisRound.push(enc.currentTurnParticipantId);
+  const cap = (enc.participants.length + 2) * 2;
+  let guard = 0;
+
+    // BISECT: dmg+heal+cond+add+pause
+    const actor = enc.participants.find(p => p.id === enc.currentTurnParticipantId);
+    if (actor) {
+      const foes = enc.participants.filter(p => p.id !== actor.id && p.currentHp > 0 && p.isActive !== false);
+      if (foes.length > 0) {
+        const tgt = foes[Math.floor(Math.random() * foes.length)];
+        const dmg = 1 + Math.floor(Math.random() * 5);
+        apply(applyHpChange(enc, tgt.id, 'damage', dmg), `damage ${actor.name}→${tgt.name} -${dmg}`);
+      }
+    }
+    if (actor && actor.name === 'Cleric' && totalTurns % 2 === 0) {
+      const wounded = enc.participants.filter(p => p.currentHp > 0 && p.currentHp < p.maxHp).sort((a,b)=>(a.currentHp/a.maxHp)-(b.currentHp/b.maxHp));
+      if (wounded.length > 0) {
+        const tgt = wounded[0]; const amt = 2 + Math.floor(Math.random()*5);
+        apply(applyHpChange(enc, tgt.id, 'heal', amt), `heal ${tgt.name} +${amt}`);
+      }
+    }
+    if (totalTurns % 4 === 0) {
+      const living = enc.participants.filter(p => p.currentHp > 0 && p.isActive !== false);
+      if (living.length > 0) {
+        const tgt = living[Math.floor(Math.random()*living.length)];
+        apply(toggleCondition(enc, tgt.id, 'stunned'), `condition stunned on ${tgt.name}`);
+      }
+    }
+    if (totalTurns % 9 === 0 && totalTurns > 0) {
+      const living = enc.participants.filter(p => p.currentHp > 0);
+      if (living.length > 0) {
+        const tgt = living[Math.floor(Math.random()*living.length)];
+        apply(toggleParticipantActive(enc, tgt.id), `toggleActive ${tgt.name}`);
+      }
+    }
+    if (totalTurns % 5 === 0 && totalTurns > 0) {
+      const dead = enc.participants.find(p => p.currentHp <= 0);
+      if (dead) apply(removeParticipant(enc, dead.id), `remove ${dead.name}`);
+    }
+    if (totalTurns % 10 === 0 && totalTurns > 0) {
+      const newP = makeParticipant({ id: `r${totalTurns}`, name: `R${totalTurns}`, type: 'monster', initiative: 9, maxHp: 100, currentHp: 100 });
+      apply(addParticipant(enc, newP), `add ${newP.name}`);
+    }
+    //REMOVED
+    //REMOVED
+    // 9. pause — re-enabled, isolating interaction
+    if (totalTurns % 12 === 0 && totalTurns > 0) {
+      apply(togglePause(enc), 'pause');
+    }
+
+    while (enc.round === startRound && guard < cap) {
+      // advance FIRST, then check wrap before recording
+      let t;
+      try { t = nextTurn(enc); } catch (e) { log(`nextTurn ERR: ${e.message}`); break; }
+      apply(t, 'nextTurn');
+      // stop at round wrap — nextTurn just rolled into new round
+      if (enc.round !== startRound) break;
+      totalTurns++;
+      seenThisRound.push(enc.currentTurnParticipantId);
+      guard++;
+      if (!enc.isStarted) break;
+    }
+
+  // audit this round
+  const uniq = new Set(seenThisRound);
+  const dupes = seenThisRound.filter(id => seenThisRound.indexOf(id) !== seenThisRound.lastIndexOf(id));
+  if (dupes.length > 0 || uniq.size < seenThisRound.length) {
+    violations.push({ round: roundN, seen: seenThisRound.map(id => enc.participants.find(p=>p.id===id)?.name||id), dupes });
+    if (violations.length <= 3) {
+      console.log(`\n=== VIOLATION round ${roundN} ===`);
+      console.log(`  seen: ${seenThisRound.map(id => enc.participants.find(p=>p.id===id)?.name||id).join(' → ')}`);
+      console.log(`  dupes: ${[...new Set(dupes)].map(id => enc.participants.find(p=>p.id===id)?.name||id).join(', ')}`);
+      // print op log for this round
+      const roundOps = opLog.filter(o => o.round === startRound || o.round === roundN);
+      console.log(`  ops: ${roundOps.map(o => o.label).join(' | ')}`);
+    }
+  }
+
+  if (!enc.isStarted) { console.log('encounter ended'); break; }
+
+  // revive dead
+  const dead = enc.participants.filter(p => p.currentHp <= 0 || p.isActive === false);
+  for (const d of dead) {
+    if (d.isActive === false) apply(toggleParticipantActive(enc, d.id), `revive-reactivate ${d.name}`);
+    apply(applyHpChange(enc, d.id, 'heal', d.maxHp), `revive-heal ${d.name} →${d.maxHp}`);
+  }
+}
+
+console.log(`\ntotal violations: ${violations.length} / ${ROUNDS} rounds`);
+if (violations.length > 0) {
+  console.log('first 5:', violations.slice(0,5).map(v => `r${v.round}`));
+}

tests/audit/audit-state.js

@@ -0,0 +1,231 @@
+// DEPRECATED — DO NOT USE.
+// Random simulation gave false 0-violations while replay (exact ops)
+// reproduced real bugs. Replay-mirror approach = duplicate work.
+// Kept for now in case parts reusable. Will delete once log analyzer
+// (scratch/) + unit tests cover the ground.
+//
+// Prefer: replay-combat.js dumps turnOrderIds per turn, log analyzer
+// finds dupes/skips from real run. Unit tests lock confirmed bugs.
+//
+// To revive: delete this early-return block below.
+if (require.main === module) {
+  console.error('audit-state.js DEPRECATED. See header comment.');
+  process.exit(0);
+}
+
+// === original (below) — exploratory bug-finder, kept for reference ===
+// Expanded bug-finder: runs combat through pure turn.js, audits invariant
+// checks per round across multiple bug classes (not just rotation).
+// NOT a unit test (Math.random, exploratory). Unit tests lock known bugs.
+//
+// Bug classes audited:
+//   1. Rotation integrity  (skip/dupe per round)  — BUG-1, BUG-3
+//   2. HP invariants       (0<=hp<=max, no NaN)
+//   3. Condition toggles   (consistent, applied/removed)
+//   4. isActive consistency (dead=inactive, alive=active after ops)
+//   5. turnOrderIds        (no dup ids, no orphan/dead ids, subset of active)
+//   6. currentTurn         (valid id, in turnOrderIds, isActive)
+//   7. deathSave counter   (0<=saves<=3, reset on revive)
+//   8. removeParticipant   (turnOrderIds updated, currentTurn updated)
+//   9. Undo                (every op.patch has .log.undo; roundtrip restores)
+//
+// Run: node scripts/audit-state.js [rounds]
+
+'use strict';
+const shared = require('../../shared');
+const {
+  makeParticipant, startEncounter, nextTurn, togglePause,
+  addParticipant, updateParticipant, removeParticipant,
+  toggleParticipantActive, applyHpChange, deathSave,
+  toggleCondition, reorderParticipants, endEncounter,
+} = shared;
+
+const ROUNDS = parseInt(process.argv[2], 10) || 100;
+
+function p(id, init, extra = {}) {
+  return makeParticipant({
+    id, name: id, type: 'monster',
+    initiative: init, maxHp: 200, currentHp: 200,
+    ...extra,
+  });
+}
+function enc(ps) {
+  return { name:'a', participants:ps, isStarted:false, isPaused:false,
+    round:0, currentTurnParticipantId:null, turnOrderIds:[] };
+}
+
+const ps = [
+  p('c1', 14, { type:'character' }), p('c2', 10, { type:'character' }),
+  p('c3', 15, { type:'character' }), p('m1', 12), p('m2', 12),
+  p('m3', 11, { maxHp:500, currentHp:500 }), p('m4', 13),
+  p('n1', 8, { maxHp:150, currentHp:150, isNpc:true }),
+];
+
+let e = enc(ps);
+const violations = [];
+
+function check(label, cond, detail) {
+  if (!cond) violations.push({ label, detail, round: e.round, state: snap(e) });
+}
+
+function snap(x) {
+  return JSON.stringify({
+    round: x.round, isStarted: x.isStarted, isPaused: x.isPaused,
+    current: x.currentTurnParticipantId,
+    order: x.turnOrderIds,
+    hp: x.participants.map(p => `${p.id}:${p.currentHp}/${p.maxHp}${p.isActive===false?'-': ''}`),
+    dead: x.participants.filter(p => p.currentHp <= 0).map(p => p.id),
+    inactive: x.participants.filter(p => p.isActive === false).map(p => p.id),
+  });
+}
+
+// start
+e = { ...e, ...startEncounter(e).patch };
+let totalTurns = 0;
+
+for (let roundN = 1; roundN <= ROUNDS; roundN++) {
+  const startRound = e.round;
+
+  // ops (mirror replay)
+  const actor = e.participants.find(p => p.id === e.currentTurnParticipantId);
+  if (actor) {
+    const foes = e.participants.filter(p => p.id !== actor.id && p.currentHp > 0 && p.isActive !== false);
+    if (foes.length > 0) {
+      const tgt = foes[Math.floor(Math.random() * foes.length)];
+      const dmg = 1 + Math.floor(Math.random() * 5);
+      try { e = { ...e, ...applyHpChange(e, tgt.id, 'damage', dmg).patch }; } catch (err) {}
+    }
+    if (actor.name === 'c2' && totalTurns % 2 === 0) {
+      const wounded = e.participants.filter(p => p.currentHp > 0 && p.currentHp < p.maxHp)
+        .sort((a,b)=>(a.currentHp/a.maxHp)-(b.currentHp/b.maxHp));
+      if (wounded.length > 0) {
+        try { e = { ...e, ...applyHpChange(e, wounded[0].id, 'heal', 2+Math.floor(Math.random()*5)).patch }; } catch (err) {}
+      }
+    }
+  }
+  if (totalTurns % 4 === 0) {
+    const living = e.participants.filter(p => p.currentHp > 0 && p.isActive !== false);
+    if (living.length > 0) {
+      const tgt = living[Math.floor(Math.random()*living.length)];
+      try { e = { ...e, ...toggleCondition(e, tgt.id, 'stunned').patch }; } catch (err) {}
+    }
+  }
+  if (totalTurns % 9 === 0) {
+    const living = e.participants.filter(p => p.currentHp > 0);
+    if (living.length > 0) {
+      const tgt = living[Math.floor(Math.random()*living.length)];
+      try { e = { ...e, ...toggleParticipantActive(e, tgt.id).patch }; } catch (err) {}
+    }
+  }
+  if (totalTurns % 5 === 0) {
+    const dead = e.participants.find(p => p.currentHp <= 0);
+    if (dead) { try { e = { ...e, ...removeParticipant(e, dead.id).patch }; } catch (err) {} }
+  }
+  // mid-round revive: DM reactivates a downed participant's turn (mirrors
+  // replay-combat.js + real play). Triggers same path as revive-between-rounds
+  // but INSIDE rotation — where BUG-5 lives.
+  if (totalTurns % 7 === 0 && totalTurns > 0) {
+    const down = e.participants.find(p => p.currentHp <= 0 || p.isActive === false);
+    if (down) {
+      try {
+        if (down.isActive === false) e = { ...e, ...toggleParticipantActive(e, down.id).patch };
+        e = { ...e, ...applyHpChange(e, down.id, 'heal', down.maxHp).patch };
+      } catch (err) {}
+    }
+  }
+  if (totalTurns % 10 === 0 && totalTurns > 0) {
+    const np = makeParticipant({ id: `r${totalTurns}`, name:`R${totalTurns}`, type:'monster', initiative:9, maxHp:100, currentHp:100 });
+    try { e = { ...e, ...addParticipant(e, np).patch }; } catch (err) {}
+  }
+  if (totalTurns % 12 === 0) {
+    try { e = { ...e, ...togglePause(e).patch }; } catch (err) {}
+    try { e = { ...e, ...togglePause(e).patch }; } catch (err) {}
+  }
+
+  // advance until round wraps or cap
+  const cap = (e.participants.length + 4) * 2;
+  let guard = 0;
+  const seenThisRound = [];
+  while (e.round === startRound && guard < cap) {
+    if (e.currentTurnParticipantId) seenThisRound.push(e.currentTurnParticipantId);
+    if (e.isPaused) { check('advance-while-paused', false, 'paused at advance'); break; }
+    let t;
+    try { t = nextTurn(e); } catch (err) { check('nextTurn-throws', false, err.message); break; }
+    e = { ...e, ...t.patch };
+    if (e.round !== startRound) break;
+    totalTurns++;
+    guard++;
+    if (!e.isStarted) break;
+  }
+
+  // === audits ===
+  // 1. rotation (this round, before wrap)
+  const uniq = new Set(seenThisRound);
+  check('rotation-dupes', uniq.size >= seenThisRound.length,
+    `seen ${seenThisRound.length} uniq ${uniq.size}: ${JSON.stringify(seenThisRound)}`);
+
+  // 2. HP invariants
+  for (const p of e.participants) {
+    check(`hp-valid:${p.id}`, typeof p.currentHp === 'number' && !isNaN(p.currentHp) && p.currentHp >= 0 && p.currentHp <= p.maxHp,
+      `hp=${p.currentHp} max=${p.maxHp}`);
+  }
+  // 3. isActive consistency: dead should be inactive (after applyHpChange)
+  for (const p of e.participants) {
+    check(`dead-inactive:${p.id}`, p.currentHp > 0 || p.isActive === false,
+      `hp=${p.currentHp} isActive=${p.isActive}`);
+  }
+  // 4. turnOrderIds no dup
+  const orderUniq = new Set(e.turnOrderIds);
+  check('turnOrder-no-dup', orderUniq.size === e.turnOrderIds.length,
+    `order ${JSON.stringify(e.turnOrderIds)}`);
+  // 5. turnOrderIds all active
+  for (const id of e.turnOrderIds) {
+    const p = e.participants.find(x => x.id === id);
+    check(`turnOrder-active:${id}`, p && p.isActive !== false,
+      `isActive=${p && p.isActive}`);
+  }
+  // 6. currentTurn valid
+  if (e.isStarted && e.currentTurnParticipantId) {
+    const ct = e.participants.find(x => x.id === e.currentTurnParticipantId);
+    check('currentTurn-exists', !!ct, `id=${e.currentTurnParticipantId}`);
+    if (ct) check('currentTurn-active', ct.isActive !== false, `isActive=${ct.isActive}`);
+  }
+  // 7. deathSave range
+  for (const p of e.participants) {
+    check(`deathSaves-range:${p.id}`, (p.deathSaves||0) >= 0 && (p.deathSaves||0) <= 3,
+      `saves=${p.deathSaves}`);
+    if (p.currentHp > 0 && !p.isDying) {
+      check(`deathSaves-reset:${p.id}`, (p.deathSaves||0) === 0,
+        `alive but saves=${p.deathSaves}`);
+    }
+  }
+  // 8. remove: turnOrderIds doesn't contain removed ids
+  const ids = new Set(e.participants.map(p => p.id));
+  for (const id of e.turnOrderIds) {
+    check(`turnOrder-present:${id}`, ids.has(id), `orphan id in order`);
+  }
+
+  if (!e.isStarted) { console.log('encounter ended early'); break; }
+
+  // revive dead each round (sustain combat)
+  const dead = e.participants.filter(p => p.currentHp <= 0 || p.isActive === false);
+  for (const d of dead) {
+    try {
+      if (d.isActive === false) e = { ...e, ...toggleParticipantActive(e, d.id).patch };
+      e = { ...e, ...applyHpChange(e, d.id, 'heal', d.maxHp).patch };
+    } catch (err) {}
+  }
+}
+
+// 9. undo: every op returns log.undo
+const undoOps = ['startEncounter','nextTurn','applyHpChange','toggleCondition','toggleParticipantActive','addParticipant','removeParticipant','togglePause'];
+console.log('\n=== undo support (static check) ===');
+console.log('checked via log fields at runtime; this harness discards logs');
+
+console.log(`\n=== VIOLATIONS: ${violations.length} / ${ROUNDS} rounds ===`);
+const byLabel = {};
+for (const v of violations) byLabel[v.label] = (byLabel[v.label]||0) + 1;
+const sorted = Object.entries(byLabel).sort((a,b)=>b[1]-a[1]);
+for (const [label, count] of sorted) console.log(`  ${count}x ${label}`);
+console.log('\nfirst 5 examples:');
+for (const v of violations.slice(0,5)) console.log(`  r${v.round} ${v.label}: ${v.detail}`);