- Implement error boundaries with graceful fallbacks for all major components
(sidebar, email list, email viewer, composer)
- Add push notifications via EventSource for real-time email updates
- Show connection status indicator in sidebar footer
- Play notification sound and show toast for new emails
- Add global error handler and error reporting utilities
- Configure ESLint with modern flat config
- Various fixes: unused variable warnings, proper cleanup on disconnect
- Update translations for error messages (EN/FR)
