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/api/mod.rs

@@ -1,6 +1,8 @@
 pub mod agent_api;
 pub mod face_recognition;
+pub mod five_w1h_agent_api;
 pub mod identities;
+pub mod identity_agent_api;
 pub mod identity_api;
 pub mod identity_binding;
 pub mod middleware;
@@ -8,6 +10,7 @@ pub mod n8n_search;
 pub mod person_identity;
 pub mod search;
 pub mod server;
+pub mod snapshot_api;
 pub mod universal_search;
 pub mod visual_chunk_search;
 pub mod who;