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/utils/pose_action_decoder.py

@@ -18,12 +18,10 @@ Output:
 3. Action visualization (timeline plot)
 """
 
-import sys
 import json
 import argparse
-import numpy as np
 import matplotlib.pyplot as plt
-from typing import Dict, List, Optional
+from typing import Dict, List
 from collections import defaultdict
 
 
@@ -445,29 +443,29 @@ def print_action_report(action_data: Dict) -> None:
         print(f"{'='*70}")
         
         summary = data["action_summary"]
-        print(f"\nSummary:")
+        print("\nSummary:")
         print(f"  Total Actions: {summary['total_actions']}")
         print(f"  Unique Actions: {summary['unique_actions']}")
         print(f"  Complex Actions: {summary['complex_action_count']}")
         print(f"  Stable Percentage: {summary['stable_percentage']}%")
         
-        print(f"\nAction Counts:")
+        print("\nAction Counts:")
         for action, count in sorted(summary["action_counts"].items(), key=lambda x: x[1], reverse=True):
             print(f"  {action}: {count}")
         
-        print(f"\nAction Timeline (前 10 个):")
+        print("\nAction Timeline (前 10 个):")
         timeline = data["action_timeline"]
         for act in timeline[:10]:
             print(f"  Frame {act['frame']}: {act['action']} ({act['type']}, {act['duration_frames']} frames)")
         
         if data["complex_actions"]:
-            print(f"\nComplex Actions:")
+            print("\nComplex Actions:")
             for act in data["complex_actions"]:
                 print(f"  {act['action']}: frames {act['start_frame']}-{act['end_frame']} ({act['duration_frames']} frames)")
         
         # Generate description
         desc = generate_action_description(data["action_timeline"])
-        print(f"\nHuman-readable Description:")
+        print("\nHuman-readable Description:")
         print(f"  {desc}")