feat: add cluster-agent endpoint, fix OCR labeling, fix ingestion blocking

- Add POST /api/v1/file/:file_uuid/cluster-agent endpoint for on-demand face clustering
- Fix OCR chunks being labeled as ASRX: use ChunkType.as_str() instead of {:?}
- Rule 1 now deletes old chunks before re-inserting to avoid stale data
- Add fallback face_traced.json when store_traced_faces.py fails
- ingestion_complete now handles status='error' to unblock jobs
- VLM describe tool now uses trace_id with pre-extracted face crops

src/api/mod.rs

@@ -2,6 +2,7 @@ pub mod agent_api;
 pub mod agent_search;
 pub mod auth;
 pub mod checkin_api;
+pub mod cluster_agent;
 pub mod docs;
 pub mod files;
 pub mod health;