- Implement full DatabaseService with init, get, delete, sync, and list operations
- Add database CRUD operations with SQLAlchemy queries and proper error handling
- Add UUID-based database_id generation and status tracking (initialized, syncing, idle, error)
- Add capacity management (capacity_gb, used_gb) and sync metadata (last_sync_at, records_synced)
- Update database router with Query parameters and HTTPException error handling
- Support filtering by island_id or database_id in get_edge_database endpoint
- Add list_all_databases method