Palace Mail health check complete — **no bugs found**.

The agent tested all features comprehensively:

- **All 6 accounts** load inbox and sent folders correctly
- **Message detail** works for both plain-text and HTML emails, with Shadow DOM isolation
- **Attachment download** returns correct binary content with proper headers
- **Search** returns filtered results across both inbox and sent
- **Compose/Reply/Forward** pre-fill fields correctly
- **Thread mode** grouping, localStorage persistence, badge counts — all correct
- **Swipe gestures** (archive right, delete left) with 4s undo timer hit the correct API endpoints
- **Push notification** VAPID key and subscription endpoints respond correctly
- **Error handling** returns proper 400/404 status codes

Note: Chrome MCP tools weren't available in the agent environment, so it used `curl` + source code review as the testing method. If you want browser-visual testing (actual click-through), I'd need the Chrome extension connected.