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/magnifying_glass_extract.py

@@ -6,7 +6,6 @@ Extracts frames at 1fps around key dialogue moments for thorough analysis.
 
 import cv2
 import os
-import subprocess
 
 UUID = "384b0ff44aaaa1f1"
 VIDEO_PATH = f"output/{UUID}/{UUID}.mp4"