test(e2e): harden mobile layout coverage, artifact isolation, and live pane assertions

- Store Playwright evidence in ignored test-results/ paths by default while preserving env override
- Clean up disposable temporary application data directories in /tmp on global teardown and exit signals
- Add Chromium mobile and tablet viewport profiles (phone portrait/landscape, tablet) for automated coverage
- Add a scoped Chromium mobile layout CI check on shard 1/4 to prevent redundant matrix execution
- Reach mobile Settings and Notes views via genuine sidebar navigation controls opened through the hamburger button
- Add assertions against live rendered Notes and Documents panes honoring safe-area top and height constraints
- Document local WebKit prerequisites and physical iOS/PWA test limitations in tests/e2e/README.md and package.json

tests/e2e/README.md

@@ -1,5 +1,7 @@
 # Browser End-to-End Tests
 
+## Photo Editor Release Gate
+
 The photo editor release gate launches an isolated Odysseus server on port
 `7013` with a temporary SQLite database and disposable authenticated account.
 
@@ -18,3 +20,53 @@ The disposable account is created in the temporary data directory and exercises
 owner-scoped draft and notification routes without using an existing account.
 `PHOTO_EDITOR_E2E_AUTH=0` selects the legacy unauthenticated configuration for
 investigating it; offline-upgrade coverage requires the authenticated mode.
+
+## Mobile and iOS Layout Suite
+
+The dedicated mobile and iOS layout suite exercises viewport behavior,
+accessibility zoom, scrolling, mobile safe-area geometry (Notes and Documents
+panes), and floating window restoration against an isolated local Odysseus server
+running on port `17739`.
+
+```bash
+npm install
+npm run test:ios-layout:chromium
+```
+
+### Profiles and Browser Prerequisites
+
+- **Chromium profiles** (`desktop-chromium`, `phone-chromium-portrait`, `phone-chromium-landscape`, `tablet-chromium`):
+  Provide automated baseline coverage in CI and local development without requiring
+  WebKit dependencies.
+- **WebKit profiles** (`phone-webkit-portrait`, `phone-webkit-landscape`, `tablet-webkit`):
+  Used for platform-oriented WebKit rendering validation. WebKit requires browser binaries:
+
+```bash
+npm run test:ios-layout:install
+# or: npx playwright install webkit
+npm run test:ios-layout:webkit
+```
+
+To run all installed profiles:
+
+```bash
+npm run test:ios-layout
+```
+
+### Evidence and Cleanup
+
+- **Evidence artifacts**: Screenshots are written to `test-results/ios-layout/` by
+  default and traces are written to `test-results/ios-layout-traces/`. Both paths
+  are git-ignored. Set `ODYSSEUS_LAYOUT_EVIDENCE_DIR` to override the screenshot
+  output path.
+- **Teardown**: Disposable application state and database files created in the
+  OS temporary directory are automatically cleaned up on both normal and failure
+  teardown, preserving diagnostic screenshots and failure traces.
+
+### Platform Considerations
+
+Emulated Chromium and WebKit viewports validate deterministic CSS cascade,
+computed layout geometry, viewport meta tags, and JavaScript restoration. However,
+browser emulation is not a physical device substitute: physical iOS Safari and
+standalone installed PWAs should still be verified separately for native gesture
+pinch-zoom, software keyboard dismissal transitions, and dynamic hardware notch/island insets.