feat: Swift Face Pose integration + TKG 方案 B

Major Changes:
- swift_face_pose: output pose angles (yaw/pitch/roll) in face.json
- face_processor.py: call swift_face_pose (dual output: face.json + pose.json)
- Face struct: add pose_angle field
- TKG 方案 B: gaze/lip_track nodes from face.json (no face_detections dependency)
- Chunk cleanup: delete old data before rebuild (avoid duplicate key)
- Hand nodes: classify by hand_type + gesture (15 combinations)
- HAND_OBJECT edges: bbox spatial matching (174 matches)

Test Results:
- Blake Jones: 8 faces, pose_angle ✓, 66 nodes, 174 edges
- FilmRiot: 394 faces, pose_angle ✓, 35 nodes, 39 edges
- Left hands: 132, Right hands: 2

Architecture:
- All TKG nodes built from JSON files (face.json, hand.json, yolo.json)
- Swift processors: sample_interval=3 (Face/Pose/Hand sync)
- Cleanup functions: delete_tkg_nodes_by_uuid, delete_tkg_edges_by_uuid

src/api/trace_agent_api.rs

@@ -1004,6 +1004,7 @@ async fn rebuild_tkg(
 "appearance_trace_nodes": r.appearance_trace_nodes,
 "accessory_nodes": r.accessory_nodes,
                     "object_nodes": r.object_nodes,
+                    "hand_nodes": r.hand_nodes,
                     "speaker_nodes": r.speaker_nodes,
                     "co_occurrence_edges": r.co_occurrence_edges,
                     "speaker_face_edges": r.speaker_face_edges,
@@ -1012,6 +1013,7 @@ async fn rebuild_tkg(
                     "lip_sync_edges": r.lip_sync_edges,
                     "has_appearance_edges": r.has_appearance_edges,
                     "wears_edges": r.wears_edges,
+                    "hand_object_edges": r.hand_object_edges,
                 })),
                 error: None,
             })