Updated sync-related code to use ConnectionManager instead of direct
database references:
- SyncService now creates repositories on-demand when connection available
- SyncHandler uses ConnectionManager for lazy DB access
- Added ComponentFilter and ListComponents to localdb for offline queries
- All sync operations check connection status before attempting MariaDB access
This completes the transition to offline-first architecture where all
database access goes through ConnectionManager.
Part of Phase 2.5: Full Offline Mode
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>