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/auto_identify_persons.py

@@ -105,7 +105,7 @@ def main():
 
     # 6. Generate report
     print(f"\n{'=' * 60}")
-    print(f"📊 Person Identification Results")
+    print("📊 Person Identification Results")
     print(f"{'=' * 60}")
 
     # Sort by frame count
@@ -177,7 +177,7 @@ def main():
     print(f"✅ Executed {executed} SQL statements")
 
     # 9. Generate SQL INSERT statements for person_identities
-    print(f"\n--- SQL INSERT statements for person_identities ---")
+    print("\n--- SQL INSERT statements for person_identities ---")
     for p in output["persons"][:10]:
         speaker_val = f"'{p['speaker_id']}'" if p["speaker_id"] else "NULL"
         print(