test: Add playwright main usage test

.agents/skills/playwright-e2e/reference/project-setup.md

@@ -97,7 +97,31 @@ Create `e2e/fixtures/multi-client.ts` — see [multi-client-webrtc.md](./multi-c
 
 Create `e2e/helpers/webrtc-helpers.ts` — see [multi-client-webrtc.md](./multi-client-webrtc.md) for helper functions.
 
-### 7. Add npm Scripts
+### 7. Create Isolated Test Server Launcher
+
+The app requires a signal server. Tests use an isolated instance with its own temporary database so test data never pollutes the dev environment.
+
+Create `e2e/helpers/start-test-server.js` — a Node.js script that:
+1. Creates a temp directory under the OS tmpdir
+2. Writes a `data/variables.json` with `serverPort: 3099`, `serverProtocol: "http"`
+3. Spawns `ts-node server/src/index.ts` with `cwd` set to the temp dir
+4. Cleans up the temp dir on exit
+
+The server's `getRuntimeBaseDir()` returns `process.cwd()`, so setting cwd to the temp dir makes the database go to `<tmpdir>/data/metoyou.sqlite`. Module resolution (`require`/`import`) uses `__dirname`, so server source and `node_modules` resolve correctly from the real `server/` directory.
+
+Playwright's `webServer` config calls this script and waits for port 3099 to be ready.
+
+### 8. Create Test Endpoint Seeder
+
+The Angular app reads signal endpoints from `localStorage['metoyou_server_endpoints']`. By default it falls back to production URLs in `environment.ts`. For tests, seed localStorage with a single endpoint pointing at `http://localhost:3099`.
+
+Create `e2e/helpers/seed-test-endpoint.ts` — called automatically by the multi-client fixture after creating each browser context. The flow is:
+1. Navigate to `/` (establishes the origin for localStorage)
+2. Set `metoyou_server_endpoints` to `[{ id: 'e2e-test-server', url: 'http://localhost:3099', ... }]`
+3. Set `metoyou_removed_default_server_keys` to suppress production endpoints
+4. Reload the page so the app picks up the test endpoint
+
+### 9. Add npm Scripts
 
 Add to root `package.json`: