feat: update core API, database layer, and worker modules

- Remove unused imports (n8n_search, universal_search, Client, Arc, etc.)
- Update API endpoints for identity, face recognition, search
- Fix postgres_db.rs search_videos parent_uuid column
- Add snapshot API and identity agent API
- Clean up backup files (.bak, .bak2)

src/lib.rs

@@ -22,6 +22,7 @@ pub use core::person_identity::{
 pub use core::probe::ProbeResult;
 pub use core::storage::file_manager::FileManager;
 pub use core::storage::output_dir::OutputDir;
+pub use core::storage::snapshot_manager::SnapshotManager;
 pub use core::storage::uuid;
 pub use core::thumbnail::{ThumbnailExtractor, ThumbnailResult};
 pub use ui::progress::{ProcessorType, ProgressState, ProgressUi};