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/weather_sound_detector.py

@@ -118,7 +118,7 @@ if __name__ == "__main__":
         else:
             merged_events.append(ev)
 
-    print(f"\n🎉 Analysis Complete!")
+    print("\n🎉 Analysis Complete!")
     print(f"✅ Found {len(merged_events)} weather segments.")
 
     # 統計
@@ -132,7 +132,7 @@ if __name__ == "__main__":
         json.dump({"weather_events": merged_events}, f, indent=2)
 
     # 顯示 Top 20
-    print(f"\n🔥 Top Weather Moments (Sorted by Confidence):")
+    print("\n🔥 Top Weather Moments (Sorted by Confidence):")
     sorted_ev = sorted(merged_events, key=lambda x: x["confidence"], reverse=True)
     for i, ev in enumerate(sorted_ev[:20]):
         m, s = divmod(ev["start"], 60)