Preserve stable snapshots and stabilize Electron e2e (#734)

README.md

@@ -322,6 +322,7 @@ Chain multiple skills together to create sophisticated automation pipelines. Pro
 │   ├── i18n/                # Localization resources
 │   └── types/               # TypeScript type definitions
 ├── tests/
+│   ├── e2e/                 # Playwright Electron end-to-end smoke tests
 │   └── unit/                # Vitest unit/integration-like tests
 ├── resources/                # Static assets (icons/images)
 └── scripts/                  # Build and utility scripts
@@ -354,6 +355,8 @@ pnpm package:win          # Package for Windows
 pnpm package:linux        # Package for Linux
 ```
 
+On headless Linux, run Electron tests under a display server such as `xvfb-run -a pnpm run test:e2e`.
+
 ### Communication Regression Checks
 
 When a PR changes communication paths (gateway events, chat runtime send/receive flow, channel delivery, or transport fallback), run: