Fixes#6031
- Add home and removable-media plugs for local file sync access
- Add desktop and desktop-legacy plugs for taskbar pinning in Cinnamon
- Update install hook to prompt for home interface connection
- Add documentation warnings about snap limitations and data persistence
All plugs include inline comments explaining their purpose and linking to issue.
- Test idle detection methods only once during initialization to prevent repeated failures
- Add snap environment detection with automatic method filtering
- Add proper snap plugs for system-observe and login-session-observe interfaces
- Improve DBus handling by trying gdbus first (works better in snap environments)
- Add rate-limited error logging to prevent log spam
- Add snap install hook to guide users on connecting required interfaces
- Ensure graceful fallback to 0 (not idle) when detection fails
This prevents the system freezes that occurred after hibernation due to repeated
failing idle detection attempts, and improves snap compatibility for DBus access.
