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/find_kids_refined.py

@@ -8,7 +8,6 @@ Filters:
 
 import json
 import math
-import sys
 import os
 
 POSE_JSON_PATH = "output/384b0ff44aaaa1f1/384b0ff44aaaa1f1.pose.json"
@@ -133,7 +132,7 @@ def find_kids():
 
     sorted_kids = sorted(unique_kids.values(), key=lambda x: x["timestamp"])
 
-    print(f"\nRefined Timestamps:")
+    print("\nRefined Timestamps:")
     for k in sorted_kids:
         print(
             f"  ⏱️ {k['timestamp']:.2f}s | Ratio: {k['ratio']} | Width: {k['shoulder_width']}px | Conf: {k['confidence']}"