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/search.rs

@@ -4,9 +4,6 @@
 use axum::{extract::State, http::StatusCode, response::Json, routing::post, Router};
 use serde::{Deserialize, Serialize};
 use serde_json;
-use tracing;
-
-use crate::core::db::PostgresDb;
 
 // --- Request / Response Structures ---