fix(BUG-4): updateDoc patch on activeDisplay (not setDoc replace)

All 5 storage.setDoc(activeDisplay, {...}, {merge:true}) →
storage.updateDoc(activeDisplay, {...}).

setDoc merge:true worked in prod (firebase honors merge) but ws adapter
+ mock ignore opts arg entirely → clobbers doc. updateDoc uses PATCH
across all adapters (firebase real updateDoc, ws PATCH endpoint, mock
merge). Consistent, no clobber.

Sites fixed:
- hidePlayerHp toggle
- startEncounter (set active ids)
- endEncounter (null active ids)
- deactivate active display
- activate new display

TDD: HideHpToggle.test RED first (assert updateDoc patch, impl still
setDoc → 0 calls found). GREEN after switch.

Char tests updated: Encounter.characterization (2) + Combat.characterization
(2) assert updateDoc on activeDisplay, not setDoc.

BUG-4: prod was already fixed (merge:true), test was RED due to mock
ignoring opts. Now all 3 adapters consistent via updateDoc.

.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
@@ -7,3 +6,10 @@ dist
 .env.development.local
 .env.test.local
 .env.production.local
+*.log
+data/*.sqlite
+data/*.sqlite-*
+server/data/*.sqlite
+server/data/*.sqlite-*
+/data
+/scratch

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

@@ -38,6 +38,9 @@ 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

@@ -1,15 +1,21 @@
-# TTRPG Initiative Tracker (v0.2.1)
+# TTRPG Initiative Tracker (v0.2.5)
 
-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)
+
+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!.
 
 **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)
 
 ## Features
 
+![DM View.](images/dm_view.png)
+
 * **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.
@@ -17,6 +23,7 @@ Have you tried it? Got feedback or questions? Discuss here: [https://discourse.d
 * **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 from the campaign roster (with auto-rolled initiative based on their modifier and HP pre-filled from campaign defaults) or add custom monsters.
@@ -24,16 +31,38 @@ Have you tried it? Got feedback or questions? Discuss here: [https://discourse.d
     * "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, participant HP (monster HP totals are hidden, only the bar is shown), and current turn.
-    * NPCs (monster-type) are visually distinct from hostile monsters.
-    * Displays custom campaign background if set.
-    * Shows a "Game Session Paused" message when no encounter is active or if the current encounter is paused by the DM.
-    * Player display is opened in a separate window via a button in the DM's header.
+    * 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.
 * **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:** Implemented for destructive actions like deleting campaigns, characters, encounters, or ending combat.
+* **Confirmation Modals:** Used for destructive actions like deleting campaigns, characters, encounters, or ending combat.
 
 ## Tech Stack
 
@@ -44,8 +73,7 @@ Have you tried it? Got feedback or questions? Discuss here: [https://discourse.d
 
 ## App Usage Overview
 
-![DM View Screenshot Placeholder](images/dm_view.png) 
-*(Replace with an actual screenshot of your DM view)*
+![](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:
 
@@ -65,16 +93,33 @@ The TTRPG Initiative Tracker is designed for Dungeon Masters to manage combat en
         * 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.
-        * Mark participants as inactive (e.g., if knocked out) using the toggle next to their name.
+        * 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 via `/?playerView=true` URL) shows a simplified, header-less view of the active encounter.
-    * It displays the initiative order, current turn, round number, and participant HP (monster/NPC HP values are hidden, only the bar is shown).
-    * NPCs are styled with a muted gray background, distinct from hostile monsters (custom reddish-brown) and player characters (blueish).
-    * If a custom background URL was set for the campaign, it will be displayed.
-    * If no encounter is active on the Player Display, or if the current encounter is paused by the DM, it will show an appropriate message ("Game Session Paused" or "Combat Paused").
+    * 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.
 
@@ -92,7 +137,7 @@ This flow allows the DM to prepare and run encounters efficiently while providin
 
 1.  **Clone the Repository:**
     ```bash
-    git clone <your-repository-url>
+    git clone https://code.draft13.com/robert/ttrpg-initiative-tracker
     cd ttrpg-initiative-tracker
     ```
 
@@ -183,7 +228,6 @@ This project includes a `Dockerfile` to containerize the application for deploym
 ## Project Structure
 
 <pre>
-
 ttrpg-initiative-tracker/
 ├── .dockerignore        # Specifies intentionally untracked files that Docker should ignore
 ├── .env.example         # Example environment variables
@@ -202,7 +246,6 @@ ttrpg-initiative-tracker/
 ├── App.js           # Main application component
 ├── index.css        # Global styles (including Tailwind directives)
 └── index.js         # React entry point
-
 </pre>
 
 ## Contributing

TODO.md

@@ -0,0 +1,204 @@
+# TODO
+
+Backlog of bugs + long-term items, from user. Milestones live in
+REWORK_PLAN.md.
+
+## Feature backlog
+
+### CRITICAL BUG - storage
+ - docker for sql is not using persistant storage...
+
+### feat - campaign section rollup
+
+### feat - add all characters to participants list
+
+### FEAT-M6: Transactional undo (moved from REWORK_PLAN)
+- 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 working for existing entries until cleared; new
+  format for new entries.
+- Related: BUG-7 (reorder no undo).
+
+## Architecture: 1-list turn order model (DONE)
+- Single source: turnOrderIds === participants.map(id). No re-sort after
+  startEncounter. nextTurn skips inactive (predicate), inactive stay in slot.
+- Drag (reorder) overrides initiative --- cross-init allowed, DM choice.
+- startEncounter sorts ALL participants by init once, then frozen.
+- addParticipant splices by init pos. remove/toggle/reorder sync list.
+- Display renders participants[] directly (no sortParticipantsByInitiative).
+- BUG-6 (reorder divergence) fixed structurally. BUG-5 (rotation) held
+  (500 rounds CLEAN).
+
+### FEAT-3: initiative first-class entry (add + edit)
+- Current: only initMod at char-build. No initiative field at add-participant
+  or edit. 3-step to set after other steps.
+- Need: initiative field at add-char, add-monster, AND edit participant.
+- Separate design + RED. Own work item.
+- Related: tie-break = drag order (current, works). Expose clearly.
+
+### FEAT-1: Dead participants stay in turn order --- DONE
+- Fixed: `applyHpChange` no longer flips `isActive` or touches `turnOrderIds`
+  on death/revive. Dead stay in rotation, `nextTurn` visits them, PCs get
+  death-save turn. `isActive` = DM toggle only.
+- Tests: `shared/tests/turn.dead-skip.test.js` (4 green). Char tests updated
+  to new behavior.
+
+### FEAT-2: upgrade app internal logs to be parseable
+- Goal: combat logs in Firestore store enough structured state to run
+  skip/rotation analysis on ANY historic round --- not just replay stdout.
+- Current logs: `{timestamp, message, encounterName, undo}`. Parser must
+  guess roster from message strings. Brittle.
+- Upgrade: add 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 (adapter fetch).
+  Works on real game sessions, any round, deterministic.
+- Parser scaffold NOW ingests replay stdout only (stopgap until FEAT-2).
+
+## Confirmed bugs (tests written, NOT fixed)
+
+### BUG-1: addParticipant + pause/resume corrupts turn rotation
+- **RESOLVED** as side effect of BUG-2 fix (dup-id rejection broke chain).
+- Audit: 0 violations / 100 rounds after BUG-2 fix.
+- Replay: 10 rounds clean, no skip/dupe.
+- Audit: 128 violations / 100 rounds, 4 symptom faces.
+- Symptom chain (one bug family):
+  1. pause blocks nextTurn advance → totalTurns stays frozen (e.g. 120)
+  2. addParticipant re-adds same `r${totalTurns}` id (BUG-2: no dedup)
+  3. togglePause resume rebuilds turnOrderIds → dup id appears x2
+  4. nextTurn gets stuck on dup id → rotation breaks
+  5. eventually nextTurn throws 'Encounter not running'
+- Symptom counts (audit-state.js, 100 rounds):
+  62x turnOrder-no-dup, 52x rotation-dupes, 14x nextTurn-throws
+- Repro in replay round 10+: current stuck on one participant forever,
+  nextTurn returns same id, round never advances.
+- Clean minimal repro (shared/tests/turn.pause-add.test.js) PASSES = combo
+  needs more state than single add+pause. Audit authoritative repro.
+- Clean subsystems (zero violations): HP bounds, isActive, deathSave
+  range, conditions, removeParticipant orphans.
+- Real repro = `node scripts/audit-state.js` (or audit-rotation.js).
+
+### BUG-2: addParticipant allows duplicate id
+- **FIXED** (commit: addParticipant throws on dup id).
+- Test: `shared/tests/turn.characterization.test.js` 'addParticipant rejects
+  duplicate id' --- GREEN.
+
+### bug-3 was a halucination has been removed
+
+### BUG-4: hide-player-HP breaks display view (preexisting) --- PROD FIXED, TEST RED (mock bug)
+- **Broader than hide-HP**: ALL 5 `storage.setDoc(getPath.activeDisplay(), ...)` calls
+  use `{merge:true}` which is IGNORED (setDoc = replace per contract).
+  Each write clobbers other fields on activeDisplay/status doc.
+  - line 1619: hide-HP toggle → clobbers campaignId+encounterId (display paused)
+  - line 1648: start combat → clobbers hidePlayerHp
+  - line 1779: end combat → clobbers hidePlayerHp
+  - line 1997: deactivate → clobbers hidePlayerHp
+  - line 2002: activate → clobbers hidePlayerHp
+- Toggle "hide player HP" in admin → display view flips to "Game Session Paused".
+- Toggling back does NOT recover. Must re-activate encounter in encounters
+  panel to restore display.
+- Expected: hide-HP toggle updates one field on activeDisplay/status doc,
+  display stays live on current encounter.
+- Likely cause: toggle writes to wrong path, or clobbers activeCampaignId/
+  activeEncounterId with null (setDoc replace vs updateDoc patch).
+- Fix: use updateDoc (patch) not setDoc (replace); or include all existing
+  fields when writing.
+- Status update (2026-07): all 5 sites now use `{merge:true}`. Real firebase
+  adapter honors merge → production works. BUT jsdom test still RED because
+  `src/__mocks__/firebase/firestore.js` setDoc records call, IGNORES opts
+  (no actual merge). Mock must simulate firebase merge semantics for test
+  to pass. Fix = mock setDoc: if opts.merge, MOCK_DB.merge(path,data) else
+  replace. OR change App.js setDoc(merge) → updateDoc (cleaner, ws adapter
+  uses PATCH). Decide which.
+- Test: render App + DisplayView, toggle hide-HP, assert display still shows
+  encounter (not paused).
+
+### BUG-5: mid-round addParticipant/revive corrupts rotation --- FIXED
+- Fixed (commit `494327f`). Slot-array turn order + DRY advance core
+  `nextActiveAfter`. Both nextTurn + computeTurnOrderAfterRemoval delegate.
+- 500-round replay: 0 skips, 0 double-acts.
+
+### BUG-6: reorderParticipants doesn't update turnOrderIds --- FIXED
+- Fixed structurally by 1-list model (commit 5d3a060). turnOrderIds =
+  participants.map(id) always. reorder cross-init allowed (DM override).
+  Display === rotation by construction.
+- Test: `shared/tests/turn.reorder.test.js` 'reorder updates turnOrderIds' (RED).
+- `reorderParticipants(enc, draggedId, targetId)` swaps two same-initiative
+  participants in `participants[]` array but leaves `turnOrderIds` unchanged.
+- nextTurn rotates via `turnOrderIds` only → reorder has NO effect on combat
+  rotation. Mid-encounter drag-drop = pointless.
+- replay-combat.js calls reorderParticipants with WRONG signature
+  `(enc, reorderedArray)` --- swallowed by try/catch, silent no-op. So
+  replay never exercised real path either.
+- Fix: reorder must also update turnOrderIds to match new participant order
+  (within same-initiative tie).
+
+### BUG-7: reorderParticipants has no undo
+- Test: `shared/tests/turn.undo.test.js` 'reorderParticipants has no undo' (GREEN doc).
+- `reorderParticipants` returns `log: null`. Other ops return `log.undo`.
+- Cannot undo drag-drop. Candidate for undo system (M6).
+
+### BUG-8: ws adapter has no reconnect
+- Test: `server/tests/ws-reconnect.test.js` (RED).
+- WS dies (idle/error/close) → `wsReady=null`, subscribers dead forever.
+- Display frozen until full reload.
+- Fix: `onclose` → reconnect + re-subscribe existing paths.
+
+### BUG-10: deact+reactivate same round double-acts participant
+- Discovered in 500-round replay (3 occurrences). DISTINCT from BUG-5.
+- Pattern: participant acts → DM deactivates them → DM reactivates them
+  same round → `computeTurnOrderAfterAddition` re-inserts by initiative
+  (front) → acts AGAIN before round ends.
+- No "acted-this-round" guard. Slot-array model has no per-round-acted set.
+- Edge case (DM deact+reactivate same participant same round).
+- Fix candidate: track actedThisRound set, skip re-acted; OR insertion
+  places reactivate AFTER current position (not by initiative).
+- Parser now discounts deact-current advances, so this surfaced real.
+
+### BUG-11: FE Combat.scenario test crashes (pre-existing)
+- `src/tests/Combat.scenario.test.js:254` deathSave query helper throws
+  (button not found).
+- Baseline (my changes removed) also exit=1. Pre-existing, not regression.
+- Crashes whole FE test run (process dies).
+
+### BUG-13: reorderParticipants crossing current pointer = ambiguous acted-semantics
+- Discovered 7/1 replay. `reorderParticipants` (shared/turn.js:522) = pure
+  drag, no pointer logic. Swapping two actors across current pointer mid-round
+  = ambiguous who-acted-this-round. Earlier replay arbitrary swaps showed
+  skip/double (R9 Summon3 2x, R11 Goblin1 2x) before fix restricted swaps to
+  upcoming-only.
+- Replay now avoids crossing (adjacent upcoming pair only, commit af165f4).
+  Real app untested: if DM drags actor past current pointer mid-round, skip/
+  double behavior undefined.
+- Decide: block cross-pointer reorder, or define acted-semantics. RED needed.
+
+### BUG-14: addParticipant init-insertion breaks after drag-reorder
+- Discovered 7/1 replay. `computeTurnOrderAfterAddition` scans for first id
+  with init < addedInit, assumes list init-sorted. After drag, list NOT sorted
+  → scan hits wrong slot.
+- Trace turn 30→31: list `[Goblin1:20,Goblin2:22,...]` (drag moved Goblin1
+  before Goblin2). Add Reinforce3 init 21 → scan hits Goblin1:20 (idx 0, <21)
+  first → insert at 0. Should slot after Goblin2:22. WRONG.
+- Root conflict: 1-list model = drag source of truth (no re-sort); addParticipant
+  = init-based insertion (needs sorted list). After ANY drag, add-insertion
+  meaningless.
+- Proposed fix: append to end always (option A). DM drags to position. Matches
+  drag = source of truth. Makes `computeTurnOrderAfterAddition` trivial.
+- Related: FEAT-3 (initiative first-class field).
+
+## Pipeline (bugs only --- milestones live in REWORK_PLAN.md)
+- [ ] BUG-4: fix setDoc→updateDoc for all 5 activeDisplay sites
+- [x] BUG-5: fixed (1-list model, 500 rounds clean)
+- [x] BUG-6: fixed structurally (1-list model)
+- [x] BUG-12: fixed --- campaign selection follows activeDisplay
+- [x] BUG-15: fixed --- DisplayView no longer re-sorts (drag order preserved)
+- [x] BUG-8: ws adapter reconnect (implemented + GREEN)
+- [ ] BUG-10: deact+reactivate double-act
+- [ ] BUG-11: FE Combat.scenario crash
+- [ ] BUG-13: reorder cross-pointer semantics (RED + decide block/allow)
+- [ ] BUG-14: addParticipant init-insert breaks post-drag (append? + RED)

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 (ws storage, same-origin via caddy)
+ARG REACT_APP_TRACKER_APP_ID=ttrpg-initiative-tracker-default
+ENV REACT_APP_STORAGE=ws
+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 +1,274 @@
+# 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
+
+### Backend (dev)
+
+```bash
+npm run server:dev        # :4001, db: server/data/tracker.sqlite
+# or direct:
+DB_PATH=./data/tracker.sqlite PORT=4001 node server/index.js
+```
+
+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.
+
+### Frontend (dev server, ws mode)
+
+```bash
+REACT_APP_STORAGE=ws \
+REACT_APP_BACKEND_URL=http://127.0.0.1:4001 \
+REACT_APP_BACKEND_WS=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
+- `ws`/`memory` → stub auth + db sentinel, route via `storage.*` adapter
+
+## Test layers
+
+- **Layer 1**: App vs firebase mock. Proves adapter call shape. Never exercises ws adapter.
+- **Layer 2**: ws 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,ws,memory}.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** | ws adapter vs live backend. Proves translation + path identity. |

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 |
+| `ws.js` | `STORAGE=ws` — 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)
+      ws.js                 # NEW — talks to backend
+      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+ws+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 + ws + 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/ws.js` per interface, talking to backend. Generic KV ops, subscribes to WS.
+- 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=ws`.
+- 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 (ws 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 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=ws` → 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=ws`
+- 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 +1,234 @@
+# 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 (ws mode)
+```bash
+REACT_APP_STORAGE=ws \
+REACT_APP_BACKEND_URL=http://127.0.0.1:4001 \
+REACT_APP_BACKEND_WS=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
+- `ws` → backend (docker/prod)
+- `memory` → in-process (test seed)
+
+All adapters ESM. Adapter contract: `src/storage/contract.js` — same spec vs memory/ws/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.

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 +2,33 @@
   "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": "npm run shared:test && npm run server:test"
   },
   "eslintConfig": {
     "extends": [

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 +1,25 @@
+# scripts/
+
+Manual demo tool. NOT test.
+
+## replay-combat.js
+
+Live backend demo. Drives full combat via ws 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, ws 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: ws storage, :3999
+if ! lsof -ti :3999 >/dev/null 2>&1; then
+  echo "starting frontend :3999..."
+  REACT_APP_STORAGE=ws \
+  REACT_APP_BACKEND_URL=http://127.0.0.1:4001 \
+  REACT_APP_BACKEND_WS=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 +1,376 @@
+// 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 { createWsStorage } = require('../src/storage/ws');
+
+const BACKEND = process.env.BACKEND_URL || 'http://127.0.0.1:4001';
+const WS_URL = process.env.BACKEND_WS || 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 = createWsStorage({ baseUrl: BACKEND, wsUrl: 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',
+];
+
+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].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);
+          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/ws.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/ws.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/ws-contract.test.js

@@ -0,0 +1,34 @@
+// Layer 2 test: exercise ws.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
+// createWsStorage 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 { createWsStorage } = require('../../src/storage/ws');
+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 = createWsStorage({ baseUrl, wsUrl });
+  storage.dispose = (done) => handle.close(done);
+  return storage;
+}
+
+runStorageContract('ws (live backend)', makeStorage);

server/tests/ws-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 { createWsStorage } = require('../../src/storage/ws');
+
+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 = createWsStorage({ baseUrl, 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({ 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 +1,6 @@
+module.exports = {
+  rootDir: '.',
+  testEnvironment: 'node',
+  testMatch: ['<rootDir>/tests/**/*.test.js'],
+  collectCoverageFrom: ['turn.js'],
+};

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/turn.characterization.test.js

@@ -0,0 +1,366 @@
+// 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,
+  computeTurnOrderAfterAddition,
+  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 keeps active + stays in turn order (FEAT-1)', () => {
+    // FEAT-1: death no longer deactivates or removes from turn order.
+    // Dead stay in rotation, nextTurn still visits them, PCs get death-save turn.
+    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(true);
+    expect(patch.turnOrderIds).toBeUndefined();
+    expect(patch.currentTurnParticipantId).toBeUndefined();
+  });
+
+  test('heal above 0 resets death saves, keeps active (FEAT-1)', () => {
+    // FEAT-1: revive no longer flips isActive (was already active — death
+    // doesn't deactivate). deathSaves still reset.
+    const ps = [p('a', 10, { currentHp: 0, 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 saves', () => {
+    const ps = [p('a', 10, { currentHp: 0, deathSaves: 0 })];
+    const { patch } = deathSave(enc(ps), 'a', 1);
+    expect(patch.participants[0].deathSaves).toBe(1);
+  });
+
+  test('clicking same save decrements (toggle)', () => {
+    const ps = [p('a', 10, { currentHp: 0, deathSaves: 2 })];
+    const { patch } = deathSave(enc(ps), 'a', 2);
+    expect(patch.participants[0].deathSaves).toBe(1);
+  });
+
+  test('third save sets isDying', () => {
+    const ps = [p('a', 10, { currentHp: 0, deathSaves: 2 })];
+    const result = deathSave(enc(ps), 'a', 3);
+    expect(result.patch.participants[0].deathSaves).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 (1-list, cross-init allowed)', () => {
+    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 allowed (1-list, DM override)', () => {
+    const ps = [p('a', 10), p('b', 5)];
+    const { patch } = reorderParticipants(enc(ps), 'a', 'b');
+    expect(patch.participants.map(x => x.id)).toEqual(['a', 'b']);
+  });
+});
+
+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('computeTurnOrderAfterAddition', () => {
+  test('not started = empty', () => {
+    const out = computeTurnOrderAfterAddition(enc([]), 'a');
+    expect(out).toEqual({});
+  });
+
+  test('returns insertAt (1-list: caller splices + syncs)', () => {
+    const e = enc([p('a',3)], { isStarted: true, turnOrderIds: ['a'], participants: [p('a',3)] });
+    const out = computeTurnOrderAfterAddition(e, 'a');
+    // already present → no-op
+    expect(out).toEqual({});
+  });
+
+  test('no-op if already present', () => {
+    const e = enc([], { isStarted: true, turnOrderIds: ['a', 'b'] });
+    const out = computeTurnOrderAfterAddition(e, 'a');
+    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 +1,257 @@
+// 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',
+];
+
+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;
+    const condQueue = [...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);
+            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, 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 });
+        }
+      }
+
+      // 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);
+  });
+});

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

@@ -0,0 +1,73 @@
+// M4 desired behavior: dead PC stays in turn order, turn still comes up,
+// deathSave fires. Current code filters isActive (set false on death) so
+// dead participants are SKIPPED. Test asserts desired state = RED on current.
+
+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('M4: dead participants stay in turn order', () => {
+  test('dead PC not removed from turnOrderIds', () => {
+    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 turn still comes up (nextTurn visits them)', () => {
+    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→b→c. b's turn should come up.
+    e = { ...e, ...nextTurn(e).patch };
+    expect(e.currentTurnParticipantId).toBe('b');
+  });
+
+  test('dead PC on their turn can deathSave', () => {
+    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 };
+    // advance to b's turn
+    e = { ...e, ...nextTurn(e).patch };
+    expect(e.currentTurnParticipantId).toBe('b');
+    // b is dead, on their turn: deathSave should not throw
+    const r = deathSave(e, 'b', 1);
+    expect(r.patch).toBeTruthy();
+    const b = r.patch.participants.find(x => x.id === 'b');
+    expect(b.deathSaves).toBe(1);
+  });
+
+  test('dead PC not 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(true);
+  });
+});

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 +1,125 @@
+// 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: allowed, list + rotation reflect new order', () => {
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e)); // [a,b,c]
+    e = apply(e, reorderParticipants(e, 'c', 'a')); // drag c before a
+    expect(e.turnOrderIds).toEqual(['c','a','b']);
+    expect(e.turnOrderIds).toEqual(e.participants.map(x => x.id));
+  });
+
+  test('reorder: rotation follows new list order', () => {
+    let e = enc([p('a',10),p('b',7),p('c',3)]);
+    e = apply(e, startEncounter(e)); // [a,b,c], cur=a
+    e = apply(e, reorderParticipants(e, 'b', 'a')); // [b,a,c], cur still a
+    const rot = walkRotation(e); // start a, next c (wrap), next b, back a
+    expect(rot).toEqual(['a','c','b']);
+  });
+
+  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.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 +1,67 @@
+// 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)', () => {
+    const ps = [p('a', 10), p('b', 20), p('c', 20)]; // b,c tie
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    // initial order: b,c,a (init 20,20,10)
+    expect(e.turnOrderIds).toEqual(['b', 'c', 'a']);
+    const r = reorderParticipants(e, 'c', 'b');
+    // drag c before b: remove c → [b,a], insert before b → [c,b,a]
+    expect(r.patch.participants.map(p => p.id)).toEqual(['c', 'b', 'a']);
+  });
+
+  test('cross-init drag allowed (1-list, DM override)', () => {
+    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.participants.map(p => p.id)).toEqual(['a', 'b']);
+  });
+
+  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 };
+    const r = reorderParticipants(e, 'c', 'b');
+    expect(r.patch.turnOrderIds).toEqual(['c', 'b', 'a']);
+    expect(r.patch.turnOrderIds).toEqual(r.patch.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', () => {
+    const ps = [p('a', 10), p('b', 20), p('c', 20)];
+    let e = enc(ps);
+    e = { ...e, ...startEncounter(e).patch };
+    // order: b,c,a
+    e = { ...e, ...reorderParticipants(e, 'c', 'b').patch };
+    expect(e.turnOrderIds).toEqual(['c', 'b', 'a']);
+  });
+});

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.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 +1,587 @@
+// @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}`;
+};
+
+// Sort used ONLY at insert points (startEncounter, addParticipant) to position
+// participants by initiative. Once positioned, turnOrderIds = participants.map(id)
+// (1-list model). No re-sort after start — drag/edit are manual overrides.
+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;
+  });
+};
+
+// 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.
+const computeTurnOrderAfterAddition = (encounter, addedId) => {
+  if (!encounter.isStarted) return {};
+  const currentIds = encounter.turnOrderIds || [];
+  if (currentIds.includes(addedId)) return {};
+  const added = (encounter.participants || []).find(p => p.id === addedId);
+  if (!added) return {};
+  // find first id with strictly lower initiative; insert before it (== after all >= )
+  const initOf = id => {
+    const p = (encounter.participants || []).find(x => x.id === id);
+    return p ? (p.initiative || 0) : 0;
+  };
+  const addedInit = added.initiative || 0;
+  let insertAt = currentIds.length;
+  for (let i = 0; i < currentIds.length; i++) {
+    if (initOf(currentIds[i]) < addedInit) { insertAt = i; break; }
+  }
+  return { insertAt }; // caller splices participants[] at this pos, then syncs
+};
+
+// ----------------------------------------------------------------------------
+// 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,
+    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 (via computeTurnOrderAfterAddition).
+function addParticipant(encounter, participant) {
+  if ((encounter.participants || []).some(p => p.id === participant.id)) {
+    throw new Error(`Participant with id "${participant.id}" already exists in encounter.`);
+  }
+  // 1-list: splice participant into participants[] by initiative position,
+  // then sync turnOrderIds = participants.map(id).
+  let updatedParticipants;
+  let insertAt;
+  if (!encounter.isStarted) {
+    updatedParticipants = [...(encounter.participants || []), participant];
+  } else {
+    const { insertAt: at } = computeTurnOrderAfterAddition(
+      { ...encounter, participants: [...(encounter.participants || []), participant] },
+      participant.id);
+    insertAt = at !== undefined ? at : (encounter.participants || []).length;
+    updatedParticipants = [
+      ...(encounter.participants || []).slice(0, insertAt),
+      participant,
+      ...(encounter.participants || []).slice(insertAt),
+    ];
+  }
+  const turnUpdates = encounter.isStarted ? syncTurnOrder(updatedParticipants) : {};
+  return {
+    patch: { participants: updatedParticipants, ...turnUpdates },
+    log: {
+      message: `${participant.name} added to encounter (Initiative: ${participant.initiative})`,
+      undo: {
+        participants: [...(encounter.participants || [])],
+        ...(encounter.isStarted ? {
+          turnOrderIds: [...(encounter.turnOrderIds || [])],
+        } : {}),
+      },
+    },
+  };
+}
+
+// ADD_PARTICIPANTS — bulk add (e.g. "add all campaign characters").
+function addParticipants(encounter, newParticipants) {
+  const updatedParticipants = [...(encounter.participants || []), ...newParticipants];
+  return { patch: { participants: updatedParticipants }, log: null };
+}
+
+// UPDATE_PARTICIPANT — edit modal save (name/initiative/hp/isNpc).
+function updateParticipant(encounter, participantId, updatedData) {
+  const updatedParticipants = (encounter.participants || []).map(p =>
+    p.id === participantId ? { ...p, ...updatedData } : p
+  );
+  return { patch: { participants: updatedParticipants }, log: null };
+}
+
+// REMOVE_PARTICIPANT — verbatim from ParticipantManager.confirmDeleteParticipant
+function removeParticipant(encounter, participantId) {
+  const updatedParticipants = (encounter.participants || []).filter(p => p.id !== participantId);
+  const advUpdates = computeTurnOrderAfterRemoval(encounter, participantId, updatedParticipants);
+  const turnUpdates = encounter.isStarted ? { ...syncTurnOrder(updatedParticipants), ...advUpdates } : {};
+  const participant = (encounter.participants || []).find(p => p.id === participantId);
+  return {
+    patch: { participants: updatedParticipants, ...turnUpdates },
+    log: {
+      message: `${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} ${newIsActive ? 'reactivated' : 'deactivated'}`,
+      undo: {
+        participants: [...(encounter.participants || [])],
+        ...(encounter.isStarted ? {
+          currentTurnParticipantId: encounter.currentTurnParticipantId,
+          turnOrderIds: [...(encounter.turnOrderIds || [])],
+        } : {}),
+      },
+    },
+  };
+}
+
+// APPLY_HP_CHANGE — verbatim from ParticipantManager.applyHpChange
+// changeType: 'damage' | 'heal'
+function applyHpChange(encounter, participantId, changeType, amount) {
+  const participant = (encounter.participants || []).find(p => p.id === participantId);
+  if (!participant) throw new Error('Participant not found.');
+  if (isNaN(amount) || amount === 0) {
+    return { patch: null, log: null }; // no-op
+  }
+  let newHp = participant.currentHp;
+  if (changeType === 'damage') newHp = Math.max(0, participant.currentHp - amount);
+  else if (changeType === 'heal') newHp = Math.min(participant.maxHp, participant.currentHp + amount);
+
+  const wasDead = participant.currentHp === 0;
+  const isDead = newHp === 0;
+  const wasResurrected = wasDead && newHp > 0;
+
+  // FEAT-1: death no longer flips isActive or touches turnOrderIds.
+  // Dead participants stay in turn order, nextTurn still visits them, PCs
+  // get their death-save turn. isActive = DM-controlled combatant toggle only.
+  const updatedParticipants = (encounter.participants || []).map(p => {
+    if (p.id !== participantId) return p;
+    const updates = { ...p, currentHp: newHp };
+    if (isDead && !wasDead) {
+      updates.deathSaves = p.deathSaves || 0;
+      updates.isDying = false;
+    }
+    if (wasResurrected) {
+      updates.deathSaves = 0;
+      updates.isDying = false;
+    }
+    return updates;
+  });
+
+  // No turn-order updates on death/revive (FEAT-1).
+  const turnUpdates = {};
+
+  const hpLine = `${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 — verbatim from ParticipantManager.handleDeathSaveChange
+// saveNumber: 1 | 2 | 3. Returns isDying flag if 3rd save hit (client triggers removal animation).
+function deathSave(encounter, participantId, saveNumber) {
+  const participant = (encounter.participants || []).find(p => p.id === participantId);
+  if (!participant) throw new Error('Participant not found.');
+  const currentSaves = participant.deathSaves || 0;
+  const newSaves = currentSaves === saveNumber ? saveNumber - 1 : saveNumber;
+
+  if (newSaves === 3) {
+    // Mark dying — caller waits for animation, then calls removeParticipant.
+    const updatedParticipants = (encounter.participants || []).map(p =>
+      p.id === participantId ? { ...p, deathSaves: newSaves, isDying: true } : p
+    );
+    return {
+      patch: { participants: updatedParticipants },
+      log: null,
+      isDying: true,
+    };
+  }
+
+  const updatedParticipants = (encounter.participants || []).map(p =>
+    p.id === participantId ? { ...p, deathSaves: newSaves } : p
+  );
+  return { patch: { participants: updatedParticipants }, log: null, isDying: false };
+}
+
+// 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'} ${conditionId}`,
+      undo: { participants: [...(encounter.participants || [])] },
+    },
+  };
+}
+
+// REORDER_PARTICIPANTS — drag-drop. 1-list model: drag overrides initiative
+// (DM choice). Cross-init drag allowed. Splices participants[], syncs turnOrderIds.
+function reorderParticipants(encounter, draggedId, targetId) {
+  const participants = [...(encounter.participants || [])];
+  const draggedIndex = participants.findIndex(p => p.id === draggedId);
+  const targetIndex = participants.findIndex(p => p.id === targetId);
+  if (draggedIndex === -1 || targetIndex === -1) {
+    throw new Error('Dragged or target item not found.');
+  }
+  const [removedItem] = participants.splice(draggedIndex, 1);
+  // recompute targetIndex after removal (shift if dragged was before target)
+  const newTargetIndex = participants.findIndex(p => p.id === targetId);
+  participants.splice(newTargetIndex, 0, removedItem);
+  const turnUpdates = encounter.isStarted ? syncTurnOrder(participants) : {};
+  return { patch: { participants, ...turnUpdates }, log: null };
+}
+
+// END_ENCOUNTER — verbatim from InitiativeControls.confirmEndEncounter
+function endEncounter(encounter) {
+  return {
+    patch: {
+      isStarted: false,
+      isPaused: false,
+      currentTurnParticipantId: null,
+      round: 0,
+      turnOrderIds: [],
+    },
+    log: {
+      message: `Combat ended: "${encounter.name}"`,
+      undo: {
+        isStarted: encounter.isStarted ?? false,
+        isPaused: encounter.isPaused ?? false,
+        round: encounter.round ?? 0,
+        currentTurnParticipantId: encounter.currentTurnParticipantId ?? null,
+        turnOrderIds: [...(encounter.turnOrderIds || [])],
+      },
+    },
+  };
+}
+
+module.exports = {
+  DEFAULT_MAX_HP,
+  DEFAULT_INIT_MOD,
+  MONSTER_DEFAULT_INIT_MOD,
+  generateId,
+  rollD20,
+  formatInitMod,
+  sortParticipantsByInitiative,
+  syncTurnOrder,
+  computeTurnOrderAfterRemoval,
+  computeTurnOrderAfterAddition,
+  makeParticipant,
+  buildCharacterParticipant,
+  buildMonsterParticipant,
+  startEncounter,
+  nextTurn,
+  togglePause,
+  addParticipant,
+  addParticipants,
+  updateParticipant,
+  removeParticipant,
+  toggleParticipantActive,
+  applyHpChange,
+  deathSave,
+  toggleCondition,
+  reorderParticipants,
+  endEncounter,
+};

src/__mocks__/firebase/_mock-db.js

@@ -0,0 +1,69 @@
+// 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
+    if (state.subscribers.has(path)) state.subscribers.get(path).forEach(cb => 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 => 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 +1,96 @@
+// 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 });
+  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);
+  // 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 {
+      const docs = MOCK_DB.collection(path);
+      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;
+}
+
+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 +1,22 @@
+// jest setup: RTL jest-dom + mock DB reset per test.
+import '@testing-library/jest-dom';
+import { resetMockDb } from './__mocks__/firebase/_mock-db';
+
+// 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 +1,232 @@
+// 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', async () => {
+        await storage.setDoc('campaigns/a', { name: 'Alpha' });
+        const doc = await storage.getDoc('campaigns/a');
+        expect(doc).toEqual({ 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({ name: 'Beta' });
+      });
+    });
+
+    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({ 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({ 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({ 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/...).
+      // Adapter must normalize internally so write+read at prefixed path round-trips
+      // AND collection queries at bare canonical path find prefixed-written docs.
+      // Catches replay-script bug (wrote prefixed, adapter reads bare, missed).
+      const PREFIX = 'artifacts/test-app/public/data';
+
+      test('setDoc prefixed then getCollection bare finds it', async () => {
+        await storage.setDoc(`${PREFIX}/campaigns/c1`, { name: 'P1' });
+        const docs = await storage.getCollection('campaigns');
+        expect(docs.some(d => d.name === 'P1')).toBe(true);
+      });
+
+      test('setDoc prefixed then getDoc same prefixed path returns it', async () => {
+        await storage.setDoc(`${PREFIX}/campaigns/c2`, { name: 'P2' });
+        const doc = await storage.getDoc(`${PREFIX}/campaigns/c2`);
+        expect(doc).toEqual({ name: 'P2' });
+      });
+
+      test('setDoc prefixed then getDoc bare path returns it', async () => {
+        await storage.setDoc(`${PREFIX}/campaigns/c3`, { name: 'P3' });
+        const doc = await storage.getDoc('campaigns/c3');
+        expect(doc).toEqual({ name: 'P3' });
+      });
+
+      test('setDoc bare then getCollection prefixed finds it', async () => {
+        await storage.setDoc('campaigns/c4', { name: 'P4' });
+        const docs = await storage.getCollection(`${PREFIX}/campaigns`);
+        expect(docs.some(d => d.name === 'P4')).toBe(true);
+      });
+    });
+
+    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({ name: 'B' });
+      });
+    });
+
+    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({ 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({ 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);
+      });
+    });
+  });
+}
+
+// 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 +1,148 @@
+// firebase.js — storage adapter wrapping Firebase SDK. Default impl (upstream-unchanged).
+// Matches interface of memory.js / ws.js so App.js calls stay identical.
+//
+// NOTE: App.js currently imports SDK directly. This adapter extracted verbatim.
+// Two-phase refactor:
+//   Phase A (now): adapter exists, wraps SDK. Hooks/writes can switch incrementally.
+//   Phase B (later): App.js imports storage factory, drops direct SDK imports.
+
+'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) {
+      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));
+    },
+
+    subscribeCollection(collectionPath, cb, queryConstraints = []) {
+      recordAdapterCall({ fn: 'subscribeCollection', path: collectionPath });
+      const q = queryConstraints.length > 0
+        ? query(collection(db, collectionPath), ...queryConstraints)
+        : collection(db, collectionPath);
+      return onSnapshot(q, (snap) => {
+        cb(snap.docs.map(d => ({ id: d.id, ...d.data() })));
+      }, (err) => console.error(`subscribeCollection ${collectionPath}:`, err));
+    },
+
+    dispose() { /* SDK managed; no-op */ },
+  };
+}
+
+// Re-export SDK pieces App.js uses directly (until full refactor).
+export {
+  doc, setDoc, updateDoc, deleteDoc, addDoc, collection, onSnapshot,
+  query, orderBy, limit, writeBatch,
+};

src/storage/index.js

@@ -0,0 +1,47 @@
+// src/storage/index.js — storage factory + SDK re-exports.
+// STORAGE=firebase (default): adapter wraps SDK. STORAGE=ws: backend.
+// 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, orderBy, limit, writeBatch,
+} from 'firebase/firestore';
+import { initFirebase, createFirebaseStorage } from './firebase';
+import { createWsStorage } from './ws';
+import { createMemoryStorage } from './memory';
+
+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 === 'ws') {
+    storageInstance = createWsStorage({
+      baseUrl: process.env.REACT_APP_BACKEND_URL || '',
+      wsUrl: process.env.REACT_APP_BACKEND_WS || '',
+    });
+  } else {
+    storageInstance = createMemoryStorage();
+  }
+  return storageInstance;
+}
+
+export function getStorageMode() {
+  return process.env.REACT_APP_STORAGE || 'firebase';
+}
+
+export {
+  initializeApp,
+  getAuth, signInAnonymously, onAuthStateChanged, signInWithCustomToken,
+  getFirestore, doc, setDoc, getDoc, getDocs, addDoc, collection,
+  onSnapshot, updateDoc, deleteDoc, query, orderBy, limit, writeBatch,
+};

src/storage/memory.js

@@ -0,0 +1,140 @@
+// memory.js — in-process storage impl. Test seed.
+// Map<docPath, data>. EventEmitter for subscribe.
+// Mirrors firebase semantics: setDoc=replace, updateDoc=shallow merge, addDoc=auto-id.
+
+'use strict';
+
+import { EventEmitter } from 'events';
+
+function createMemoryStorage() {
+  const docs = new Map();              // path -> data obj
+  const bus = new EventEmitter();
+  bus.setMaxListeners(1000);
+
+  // Firebase-prefixed paths (artifacts/{APP_ID}/public/data/...) normalized to
+  // bare canonical. Matches ws.js norm() so all impls share path identity.
+  function norm(p) {
+    if (!p) return p;
+    return p.replace(/^[\s\S]*\/public\/data\//, '');
+  }
+
+  // ---- path helpers ----
+  // collection path = path with even number of segments OR known collection.
+  // doc path = odd segments (coll/doc, coll/doc/subcoll/subdoc).
+  // getCollection(path) returns all docs whose path === path/id for any single id segment.
+  function isCollectionPath(p) {
+    return p.split('/').length % 2 === 1;
+  }
+
+  function emitDoc(path, data) { bus.emit('doc:' + path, data); }
+  function emitCollection(collPath) {
+    const children = collectionDocs(collPath);
+    bus.emit('coll:' + collPath, children);
+  }
+
+  function collectionDocs(collPath) {
+    const out = [];
+    const segLen = collPath.split('/').length + 1;
+    for (const [p, data] of docs) {
+      const segs = p.split('/');
+      if (segs.length !== segLen) continue;
+      const parent = segs.slice(0, -1).join('/');
+      if (parent === collPath) out.push(data);
+    }
+    return out;
+  }
+
+  function genId() {
+    return (typeof crypto !== 'undefined' && crypto.randomUUID)
+      ? crypto.randomUUID()
+      : `id_${Date.now()}_${Math.random().toString(36).slice(2, 10)}`;
+  }
+
+  const storage = {
+    async getDoc(rawPath) {
+      const path = norm(rawPath);
+      return docs.has(path) ? deepClone(docs.get(path)) : null;
+    },
+
+    async setDoc(rawPath, data) {
+      const path = norm(rawPath);
+      docs.set(path, deepClone(data));
+      emitDoc(path, deepClone(data));
+      const segs = path.split('/');
+      if (segs.length >= 2) emitCollection(segs.slice(0, -1).join('/'));
+    },
+
+    async updateDoc(rawPath, patch) {
+      const path = norm(rawPath);
+      const existing = docs.has(path) ? docs.get(path) : {};
+      const merged = { ...existing, ...patch };
+      docs.set(path, merged);
+      emitDoc(path, deepClone(merged));
+      const segs = path.split('/');
+      if (segs.length >= 2) emitCollection(segs.slice(0, -1).join('/'));
+    },
+
+    async deleteDoc(rawPath) {
+      const path = norm(rawPath);
+      docs.delete(path);
+      emitDoc(path, null);
+      const segs = path.split('/');
+      if (segs.length >= 2) emitCollection(segs.slice(0, -1).join('/'));
+    },
+
+    async addDoc(rawCollectionPath, data) {
+      const collectionPath = norm(rawCollectionPath);
+      const id = genId();
+      const path = `${collectionPath}/${id}`;
+      docs.set(path, deepClone(data));
+      emitDoc(path, deepClone(data));
+      emitCollection(collectionPath);
+      return { id, path };
+    },
+
+    async getCollection(rawCollPath) {
+      const collPath = norm(rawCollPath);
+      return collectionDocs(collPath).map(deepClone);
+    },
+
+    async batchWrite(ops) {
+      for (const op of ops) {
+        const mop = { ...op, path: norm(op.path) };
+        if (mop.type === 'set') await storage.setDoc(mop.path, mop.data);
+        else if (mop.type === 'delete') await storage.deleteDoc(mop.path);
+        else if (mop.type === 'update') await storage.updateDoc(mop.path, mop.data);
+      }
+    },
+
+    subscribeDoc(rawPath, cb) {
+      const path = norm(rawPath);
+      const cur = docs.has(path) ? deepClone(docs.get(path)) : null;
+      Promise.resolve().then(() => cb(cur));
+      const handler = (data) => cb(data);
+      bus.on('doc:' + path, handler);
+      return () => bus.off('doc:' + path, handler);
+    },
+
+    subscribeCollection(rawCollPath, cb) {
+      const collPath = norm(rawCollPath);
+      Promise.resolve().then(() => cb(collectionDocs(collPath).map(deepClone)));
+      const handler = (docs) => cb(docs);
+      bus.on('coll:' + collPath, handler);
+      return () => bus.off('coll:' + collPath, handler);
+    },
+
+    dispose() { bus.removeAllListeners(); docs.clear(); },
+
+    // test/debug
+    _docs: docs,
+  };
+
+  return storage;
+}
+
+function deepClone(v) {
+  if (v === null || v === undefined) return v;
+  return JSON.parse(JSON.stringify(v));
+}
+
+export { createMemoryStorage };

src/storage/ws.js

@@ -0,0 +1,237 @@
+// 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 createWsStorage({ baseUrl, wsUrl } = {}) {
+  // 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(/\/$/, '');
+  let WS;
+  if (wsUrl) {
+    WS = wsUrl;
+  } else if (typeof window !== 'undefined' && window.location) {
+    // derive from current origin (http→ws, https→wss), same host/port.
+    const proto = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
+    WS = `${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\//, '');
+  }
+
+  const docSubs = new Map();      // path -> Set<cb>
+  const collSubs = new Map();     // collPath -> Set<cb>
+  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 (doc belongs to this collection)
+    if (c.parent) {
+      const collCbs = collSubs.get(c.parent);
+      if (collCbs) {
+        const docs = await storage.getCollection(c.parent);
+        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 });
+      return res && res.data !== undefined ? res.data : null;
+    },
+
+    async setDoc(rawPath, data) {
+      const p = norm(rawPath);
+      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);
+      return await api('GET', '/api/collection', { path: p });
+    },
+
+    async batchWrite(ops) {
+      const normOps = ops.map(op => ({ ...op, path: norm(op.path) }));
+      await api('POST', '/api/batch', null, { ops: normOps });
+    },
+
+    subscribeDoc(rawPath, cb) {
+      const p = norm(rawPath);
+      // Initial value via REST (independent of WS connect).
+      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) {
+      const p = norm(rawCollPath);
+      // Initial value via REST (independent of WS connect).
+      storage.getCollection(p).then(cb).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();
+      if (typeof cb === 'function') cb();
+    },
+
+    _api: api,
+    _test: {
+      getWs: () => ws,
+      forceDrop: () => { if (ws) ws.close(); },
+      getReady: () => wsReady,
+      docSubs, collSubs,
+    },
+  };
+
+  return storage;
+}
+
+export { createWsStorage };

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 +1,137 @@
+// 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('updateDoc');
+    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('updateDoc');
+      const last = adCalls[adCalls.length - 1];
+      return last && last.data.activeCampaignId === null;
+    });
+    const adCalls = findCallActiveDisplay('updateDoc');
+    const last = adCalls[adCalls.length - 1];
+    expect(last.data).toMatchObject({ activeCampaignId: null, activeEncounterId: null });
+  });
+
+  test('toggleHidePlayerHp: updateDoc patch on activeDisplay/status', async () => {
+    await setupWithMonsters();
+    await startCombatViaUI();
+    const switchBtn = screen.getByRole('switch');
+    fireEvent.click(switchBtn);
+    await waitFor(() => {
+      const adCalls = findCallActiveDisplay('updateDoc');
+      const last = adCalls[adCalls.length - 1];
+      return last && 'hidePlayerHp' in last.data;
+    });
+    const adCalls = findCallActiveDisplay('updateDoc');
+    const last = adCalls[adCalls.length - 1];
+    expect(last.data).toHaveProperty('hidePlayerHp');
+  });
+});

src/tests/Combat.scenario.test.js

@@ -0,0 +1,340 @@
+// Combat.scenario.test.js
+// Full combat scenario: campaign -> encounter -> participants -> 100 rounds of
+// damage/heal/conditions/toggle-active/edit/death-save/pause/resume/add/remove.
+// Drives the SAME UI buttons a DM clicks. Failing assertions do NOT abort the run:
+// each phase wraps in try/catch, failures collected, final expect reports all.
+//
+// Purpose: exercise as much of the supported feature surface as possible in one
+// long combat, surfacing behavioral bugs characterization tests miss.
+
+import React from 'react';
+import { screen, fireEvent, waitFor, within } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import App from '../App';
+import {
+  renderApp, createCampaignViaUI, selectCampaignByName,
+  createEncounterViaUI, selectEncounterByName, addMonsterViaUI, setupReady,
+} from './testHelpers';
+import { getCalls, MOCK_DB } from '../__mocks__/firebase/_mock-db';
+
+// ---------- scenario helpers (UI only, same buttons as human) ----------
+
+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 }); }
+}
+
+function getParticipantForm() {
+  const heading = screen.getByText('Add Participants');
+  let node = heading;
+  for (let i = 0; i < 6; i++) {
+    node = node.parentElement;
+    if (!node) break;
+    if (node.querySelector('form')) return within(node);
+  }
+  return within(heading.parentElement);
+}
+
+// Find a participant's encounter <li> row by name. Scoped to the encounter
+// participant list (NOT the CharacterManager roster, which also shows names).
+// Encounter participant rows render an 'Init:' label; roster rows do not.
+function getParticipantRow(name) {
+  const lis = document.querySelectorAll('li');
+  for (const li of lis) {
+    const txt = li.textContent || '';
+    if (txt.includes('Init:') && txt.includes(name)) {
+      return within(li);
+    }
+  }
+  throw new Error(`encounter participant row not found: ${name}`);
+}
+
+// Character roster (CharacterManager). Assumes campaign selected.
+async function addCharacterViaUI(name, maxHp, initMod) {
+  fireEvent.change(document.getElementById('characterName'), { target: { value: name } });
+  fireEvent.change(document.getElementById('defaultMaxHp'), { target: { value: String(maxHp) } });
+  fireEvent.change(document.getElementById('defaultInitMod'), { target: { value: String(initMod) } });
+  fireEvent.click(screen.getByRole('button', { name: /^Add Character$/i }));
+  await waitFor(() => {
+    const call = getCalls().find(c => c.fn === 'updateDoc' && c.path.includes('/campaigns/') &&
+      Array.isArray(c.data.players) && c.data.players.some(p => p.name === name));
+    if (!call) throw new Error('char not persisted');
+  });
+}
+
+function setParticipantType(type) {
+  // The Type select is inside the Add Participants form.
+  const form = getParticipantForm();
+  const selects = form.getAllByRole('combobox');
+  // first combobox in the participant form is Type
+  fireEvent.change(selects[0], { target: { value: type } });
+}
+
+async function addMonsterParticipant(name, maxHp, initMod, isNpc = false) {
+  const form = getParticipantForm();
+  setParticipantType('monster');
+  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) } });
+  if (isNpc) {
+    const npcCheck = form.getByRole('checkbox', { name: /NPC/i });
+    if (!npcCheck.checked) fireEvent.click(npcCheck);
+  }
+  fireEvent.click(form.getByRole('button', { name: /Add to Encounter/i }));
+  await waitFor(() => {
+    const last = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/')).slice(-1)[0];
+    if (!last || !last.data.participants?.some(p => p.name === name)) throw new Error('monster not added');
+  });
+}
+
+async function addCharacterParticipant(charName) {
+  const form = getParticipantForm();
+  setParticipantType('character');
+  // character select is the 2nd combobox in the form after Type
+  const charSelect = form.getAllByRole('combobox')[1];
+  // find option whose text includes the char name
+  const opt = [...charSelect.querySelectorAll('option')].find(o => o.textContent.includes(charName));
+  if (!opt) throw new Error(`char option not found: ${charName}`);
+  fireEvent.change(charSelect, { target: { value: opt.value } });
+  fireEvent.click(form.getByRole('button', { name: /Add to Encounter/i }));
+  await waitFor(() => {
+    const last = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/')).slice(-1)[0];
+    if (!last || !last.data.participants?.some(p => p.name === charName)) throw new Error('char not added');
+  });
+}
+
+async function addAllCharacters() {
+  fireEvent.click(screen.getByRole('button', { name: /Add All/i }));
+  await waitFor(() => {
+    const last = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/')).slice(-1)[0];
+    if (!last) throw new Error('add all no-op');
+  });
+}
+
+function applyDamage(name, amount) {
+  const row = getParticipantRow(name);
+  const dmgBtn = row.queryByTitle('Damage');
+  if (!dmgBtn) {
+    // participant dead (Damage button hidden when currentHp===0). Expected game
+    // state over a long fight; not a bug. Skip silently.
+    return;
+  }
+  fireEvent.change(row.getByLabelText(`HP change for ${name}`), { target: { value: String(amount) } });
+  fireEvent.click(dmgBtn);
+}
+function applyHeal(name, amount) {
+  const row = getParticipantRow(name);
+  const healBtn = row.queryByTitle('Heal / Revive') || row.queryByTitle('Heal');
+  if (!healBtn) throw new Error(`${name} has no Heal button`);
+  fireEvent.change(row.getByLabelText(`HP change for ${name}`), { target: { value: String(amount) } });
+  fireEvent.click(healBtn);
+}
+function toggleActive(name) {
+  const row = getParticipantRow(name);
+  const btn = row.queryByTitle('Mark Active') || row.queryByTitle('Mark Inactive');
+  if (!btn) throw new Error(`${name} has no active toggle`);
+  fireEvent.click(btn);
+}
+function openConditions(name) {
+  const row = getParticipantRow(name);
+  const btn = row.getByTitle('Conditions');
+  // idempotent: ensure panel open. Click toggles; if another participant's panel
+  // was open it's already closed by this participant's row focus, so just click.
+  fireEvent.click(btn);
+}
+function toggleCondition(name, label) {
+  openConditions(name);
+  // panel render is async (React state). Wait for button by title.
+  return waitFor(() => {
+    const condButtons = document.querySelectorAll('button[title]');
+    const target = [...condButtons].find(b => b.getAttribute('title') === label);
+    if (!target) throw new Error(`condition button not found: ${label}`);
+    fireEvent.click(target);
+  });
+}
+function editParticipant(name, patch) {
+  const row = getParticipantRow(name);
+  fireEvent.click(row.getByTitle('Edit'));
+  // EditParticipantModal. Scope to the modal via its form inputs.
+  const modal = document.querySelector('.fixed.inset-0') || document.body;
+  const inputs = modal.querySelectorAll('input');
+  if (patch.name !== undefined) {
+    fireEvent.change(inputs[0], { target: { value: patch.name } });
+  }
+  if (patch.initiative !== undefined && inputs[1]) {
+    fireEvent.change(inputs[1], { target: { value: String(patch.initiative) } });
+  }
+  const saveBtn = modal.querySelector('button[type="submit"]') ||
+    [...modal.querySelectorAll('button')].find(b => /^Save$/i.test(b.textContent.trim()));
+  fireEvent.click(saveBtn);
+}
+function removeParticipant(name) {
+  fireEvent.click(getParticipantRow(name).getByTitle('Remove'));
+}
+async function deathSave(name, saveNum) {
+  const row = getParticipantRow(name);
+  const btn = row.getByTitle(`Death save ${saveNum}`);
+  fireEvent.click(btn);
+  await waitFor(() => {
+    const last = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/')).slice(-1)[0];
+    if (!last) throw new Error('deathSave no write');
+  });
+}
+async function nextTurn() {
+  fireEvent.click(screen.getByRole('button', { name: /Next Turn/i }));
+  await waitFor(() => {
+    const last = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/')).slice(-1)[0];
+    if (!last) throw new Error('nextTurn no write');
+  });
+}
+async function pauseCombat() {
+  fireEvent.click(screen.getByRole('button', { name: /Pause Combat/i }));
+  await waitFor(() => {
+    const last = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/')).slice(-1)[0];
+    if (!last?.data?.isPaused) throw new Error('not paused');
+  });
+}
+async function resumeCombat() {
+  fireEvent.click(screen.getByRole('button', { name: /Resume Combat/i }));
+  await waitFor(() => {
+    const last = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/')).slice(-1)[0];
+    if (last?.data?.isPaused) throw new Error('not resumed');
+  });
+}
+async function startCombat() {
+  fireEvent.click(screen.getByRole('button', { name: /Start Combat/i }));
+  await waitFor(() => {
+    const last = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/')).slice(-1)[0];
+    if (!last?.data?.isStarted) throw new Error('not started');
+  });
+}
+function toggleHidePlayerHp() {
+  fireEvent.click(screen.getByRole('switch'));
+}
+function currentEncDoc() {
+  const calls = getCalls().filter(c => c.fn === 'updateDoc' && c.path.includes('/encounters/'));
+  return calls[calls.length - 1]?.data;
+}
+
+// ---------- scenario ----------
+
+const ROUNDS = 100;
+
+test('full 100-round combat scenario', async () => {
+  await setupReady('ScenarioCamp', 'BigBoss');
+
+  // 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());
+
+  // hidden hp toggle
+  record('toggleHidePlayerHp', () => toggleHidePlayerHp());
+  record('toggleHidePlayerHp back', () => toggleHidePlayerHp());
+
+  await recordAsync('startCombat', () => startCombat());
+
+  // 100 rounds of mixed actions
+  for (let r = 1; r <= ROUNDS; r++) {
+    await recordAsync(`round ${r} nextTurn`, () => nextTurn());
+
+    // rotation integrity: turnOrderIds no dup, currentTurn valid
+    if (r % 10 === 0) {
+      record(`round ${r} rotation-check`, () => {
+        const enc = currentEncDoc();
+        if (!enc) throw new Error('no encounter doc');
+        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`);
+        }
+      });
+    }
+
+    // damage front monster every other round
+    if (r % 2 === 0) record(`round ${r} damage OrcBoss`, () => applyDamage('OrcBoss', 3));
+    if (r % 3 === 0) record(`round ${r} heal Cleric`, () => applyHeal('Cleric', 2));
+    if (r % 5 === 0) record(`round ${r} condition Fighter stunned`, () => toggleCondition('Fighter', 'Stunned'));
+    if (r % 7 === 0) record(`round ${r} toggleActive Goblin2`, () => toggleActive('Goblin2'));
+
+    // pause/resume every 10 rounds, add a participant, resume
+    if (r % 10 === 0) {
+      await recordAsync(`round ${r} pause`, () => pauseCombat());
+      await recordAsync(`round ${r} addReinforcement`, () =>
+        addMonsterParticipant(`Reinforce${r}`, 10, 1));
+      await recordAsync(`round ${r} edit Rogue initiative`, () => editParticipant('Rogue', { initiative: 20 }));
+      await recordAsync(`round ${r} resume`, () => resumeCombat());
+    }
+
+    // edit initiative on Wolf every 13
+    if (r % 13 === 0) record(`round ${r} edit Wolf init`, () => editParticipant('Wolf', { initiative: 15 }));
+
+    // damage-to-0 + death save on Rogue around round 25 and 50
+    if (r === 25) {
+      record(`round ${r} drop Rogue`, () => applyDamage('Rogue', 99));
+      record(`round ${r} deathSave1 Rogue`, () => deathSave('Rogue', 1));
+      record(`round ${r} revive Rogue`, () => applyHeal('Rogue', 22));
+    }
+    if (r === 50) {
+      record(`round ${r} drop Cleric`, () => applyDamage('Cleric', 99));
+      record(`round ${r} deathSave Cleric x3`, async () => {
+        await deathSave('Cleric', 1);
+        await deathSave('Cleric', 2);
+        await deathSave('Cleric', 3);
+      });
+      record(`round ${r} revive Cleric`, () => applyHeal('Cleric', 24));
+    }
+
+    // remove a reinforcement late
+    if (r === 30) {
+      await recordAsync(`round ${r} pause`, () => pauseCombat());
+      record(`round ${r} remove Reinforce20`, () => removeParticipant('Reinforce20'));
+      await recordAsync(`round ${r} resume`, () => resumeCombat());
+    }
+  }
+
+  await recordAsync('endCombat', async () => {
+    fireEvent.click(screen.getByRole('button', { name: /End Combat/i }));
+    // End-combat ConfirmationModal has title 'End Encounter?'. Scope Confirm to it.
+    const endConfirm = await screen.findByRole('heading', { name: /End Encounter/i });
+    const modal = endConfirm.closest('.fixed.inset-0') || document.body;
+    const confirmBtn = [...modal.querySelectorAll('button')].find(b => /Confirm/i.test(b.textContent.trim()));
+    fireEvent.click(confirmBtn);
+    await waitFor(() => {
+      const last = currentEncDoc();
+      if (last?.isStarted !== false) throw new Error('not ended');
+    });
+  });
+
+  // ---------- report ----------
+  const failed = RESULTS.filter(r => !r.ok);
+  if (failed.length > 0) {
+    const msg = failed.map(f => `FAIL [${f.phase}]: ${f.err}`).join('\n');
+    // eslint-disable-next-line no-console
+    console.error(`\n=== SCENARIO FAILURES (${failed.length}/${RESULTS.length}) ===\n${msg}\n`);
+  }
+  // eslint-disable-next-line no-console
+  console.log(`\n=== SCENARIO: ${RESULTS.length - failed.length}/${RESULTS.length} phases ok ===\n`);
+  expect(failed).toEqual([]);
+}, 240000); // long timeout: 100 rounds

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: updateDoc 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('updateDoc', 'activeDisplay/status'));
+    const call = findCall('updateDoc', 'activeDisplay/status');
+    // BUG-4 fix: updateDoc patch, not setDoc replace (was clobbering fields)
+    expect(call.data).toMatchObject({
+      activeCampaignId: expect.any(String),
+      activeEncounterId: expect.any(String),
+    });
+  });
+
+  test('togglePlayerDisplay off: updateDoc 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('updateDoc', 'activeDisplay/status'));
+
+    // turn OFF
+    const offBtn = await screen.findByTitle('Deactivate for Player Display');
+    fireEvent.click(offBtn);
+    await waitFor(() => {
+      const calls = findCalls('updateDoc', 'activeDisplay/status');
+      const last = calls[calls.length - 1];
+      return last.data.activeCampaignId === null;
+    });
+    const calls = findCalls('updateDoc', '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 +1,63 @@
+// BUG-4 repro: toggling hidePlayerHp must not clobber activeDisplay doc.
+// setDoc = replace (contract). {merge:true} arg ignored.
+// Toggling hide-HP writes {hidePlayerHp:X} alone → activeCampaignId + activeEncounterId → null.
+// Display reads null → "Game Session Paused". Recover requires re-activating encounter.
+// Fix: use updateDoc (patch), not setDoc.
+
+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/i }, { timeout: 3000 });
+
+    // toggle ON
+    fireEvent.click(toggle);
+
+    await waitFor(() => {
+      const writes = getAdapterCalls().filter(
+        c => c.fn === 'updateDoc' && c.path.includes('activeDisplay/status')
+      );
+      expect(writes.length).toBeGreaterThan(0);
+      const last = writes[writes.length - 1];
+      // patch must NOT clobber activeCampaignId/activeEncounterId.
+      // BUG: setDoc replace writes only {hidePlayerHp:true} → clobbers.
+      // Fix: updateDoc patch — other fields untouched.
+      expect(last.patch.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.endsWith(`/logs/${logId}`) && c.data.undone === true);
+      return und;
+    });
+    const markUndone = getCalls().find(c => c.fn === 'updateDoc' && c.path.endsWith(`/logs/${logId}`));
+    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('Death save 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('Death save 1'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.deathSaves === 1);
+    fireEvent.click(screen.getByTitle('Death save 2'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.deathSaves === 2);
+    fireEvent.click(screen.getByTitle('Death save 3'));
+    await waitFor(() => lastEncCall()?.data?.participants?.[0]?.isDying === true);
+    expect(lastEncCall().data.participants[0].isDying).toBe(true);
+    expect(lastEncCall().data.participants[0].deathSaves).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: ws.js + memory.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 = ['ws.js', 'memory.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/storage.test.js

@@ -0,0 +1,8 @@
+// Runner: executes storage contract against each impl.
+// TDD: contract = spec. Run against memory first. RED until memory.js built.
+'use strict';
+
+const { runStorageContract } = require('../storage/contract');
+const { createMemoryStorage } = require('../storage/memory');
+
+runStorageContract('memory', () => createMemoryStorage());

src/tests/testHelpers.js

@@ -0,0 +1,104 @@
+// 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';
+
+// 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}`);