test: Firebase mock harness + createCampaign characterization

- src/__mocks__/firebase/*: jest manual mocks (app/auth/firestore)
- src/__mocks__/firebase/_mock-db.js: in-memory DB + call recorder
- src/setupTests.js: jest-dom, env stubs, crypto polyfill, DB reset
- src/App.characterization.test.js: createCampaign -> setDoc path/payload locked
- src/storage/contract.js (renamed from .test.js, helper not suite)

21 tests green (memory 19 + createCampaign 2).

src/App.characterization.test.js

@@ -0,0 +1,69 @@
+// 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 { render, screen, fireEvent, waitFor } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import { getCalls, MOCK_DB } from './__mocks__/firebase/_mock-db';
+
+// import AFTER mocks resolve (jest auto-uses __mocks__/firebase/* via moduleNameMapper)
+import App from './App';
+
+// Helper: find first setDoc call matching path substring.
+function findCall(fn, pathSub) {
+  return getCalls().find(c => c.fn === fn && (pathSub ? c.path.includes(pathSub) : true));
+}
+
+beforeEach(() => {
+  // App reads window.location at mount; ensure clean.
+  window.history.replaceState({}, '', '/');
+  window.open = jest.fn();
+  global.alert = jest.fn();
+});
+
+describe('App -> Firebase characterization: createCampaign', () => {
+  test('setDoc called with campaign path + correct payload shape', async () => {
+    render(<App />);
+
+    // Wait past auth (mock fires instantly) and campaign list load.
+    await waitFor(() => screen.getByText(/Create Campaign/i));
+
+    fireEvent.click(screen.getByRole('button', { name: /Create Campaign/i }));
+
+    // Modal: name input + create.
+    await waitFor(() => screen.getByLabelText(/Campaign Name/i));
+    fireEvent.change(screen.getByLabelText(/Campaign Name/i), { target: { value: 'Test Campaign' } });
+    fireEvent.click(screen.getByRole('button', { name: /^Create$/i }));
+
+    await waitFor(() => {
+      const call = findCall('setDoc', '/campaigns/');
+      expect(call).toBeDefined();
+    });
+
+    const call = findCall('setDoc', '/campaigns/');
+    expect(call.path).toMatch(/campaigns\/.+$/);
+    expect(call.data).toMatchObject({
+      name: 'Test Campaign',
+      playerDisplayBackgroundUrl: '',
+      players: [],
+    });
+    expect(call.data).toHaveProperty('ownerId');
+    expect(call.data).toHaveProperty('createdAt');
+  });
+
+  test('campaign path includes APP_ID namespace', async () => {
+    render(<App />);
+    await waitFor(() => screen.getByText(/Create Campaign/i));
+    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: 'NS Test' } });
+    fireEvent.click(screen.getByRole('button', { name: /^Create$/i }));
+
+    await waitFor(() => findCall('setDoc', '/campaigns/'));
+    const call = findCall('setDoc', '/campaigns/');
+    expect(call.path).toContain('artifacts/');
+    expect(call.path).toContain('/public/data/');
+  });
+});