cleanup: remove dead code and duplicate docs

- Remove session-ses_2f27.md (161KB raw session log)
- Remove 49 ROOT_* duplicate files across REFERENCE/
- Remove 14 duplicate files between REFERENCE/ root and history/
- Remove asr_legacy.rs (dead code, replaced by asr.rs)
- Remove src/core/worker/ (duplicate JobWorker)
- Remove src/core/layers/ (empty directory)
- Remove 4 .bak files in src/
- Remove 7 dead private methods in worker/processor.rs
- Remove backup directory from git tracking

scripts/migrate_face_results.py

@@ -150,7 +150,7 @@ def migrate_results():
                 migrated_count += 1
                 print(f"  ✅ Migrated {total_faces} faces")
             else:
-                print(f"  ⚠️ Already exists, skipping")
+                print("  ⚠️ Already exists, skipping")
 
         # Commit changes
         conn.commit()
@@ -193,7 +193,7 @@ def test_api_after_migration():
 
         if response.status_code == 200:
             data = response.json()
-            print(f"✅ Success!")
+            print("✅ Success!")
             print(f"Video UUID: {data.get('video_uuid')}")
             print(f"Total faces: {data.get('total_faces')}")
             print(f"Processing time: {data.get('processing_time_secs')}s")
@@ -203,7 +203,7 @@ def test_api_after_migration():
             if isinstance(result_data, str):
                 result_data = json.loads(result_data)
 
-            print(f"\n📊 Detailed results:")
+            print("\n📊 Detailed results:")
             print(f"  Frames with faces: {result_data.get('frames_with_faces')}")
 
             gender_dist = result_data.get("gender_distribution", {})