fix: face group name read consistency, sync_file_status fix, cleanup ghost records, identity_agent replaced with face_dedup

- get_face_groups_handler: COALESCE(tp.name, tn.label) for name consistency
- sync_file_status: compare JSON vs pre_chunks (not chunk table)
- face consistency: compare frames.len() not total_faces
- cleanup 2 ghost records with NULL file_name/file_path
- replace identity_agent with face_dedup in pipeline stages
- remove identity_agent_api.rs and all references
- update required_processors to match actual processors
- update AGENTS.md with team responsibilities
- add Studio pipeline changes documentation

scripts/pose_processor.py

@@ -291,6 +291,8 @@ def _fallback(video_path, output_path, uuid, sample_interval):
         frame_count += 1
     cap.release()
     result = {"frame_count": len(frames), "fps": fps, "frames": frames}
+    if len(frames) == 0:
+        result["status"] = "no_face"
     with open(output_path, "w") as f:
         json.dump(result, f, indent=2)
     return result