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/face_embedding_extractor.py

@@ -38,7 +38,7 @@ def extract_face_embeddings(uuid: str, video_path: str):
         return {}
 
     # 1. 加載 Face JSON 數據
-    face_path = os.path.join(OUTPUT_DIR, "quick_preview", f"preview.face.json")
+    face_path = os.path.join(OUTPUT_DIR, "quick_preview", "preview.face.json")
     if not os.path.exists(face_path):
         print(f"  [Skip] No Face data for {uuid}")
         return {}
@@ -119,7 +119,7 @@ def extract_face_embeddings(uuid: str, video_path: str):
                 )
                 if result:
                     embeddings.append(np.array(result[0]["embedding"]))
-            except Exception as e:
+            except Exception:
                 # 忽略無法識別的臉部
                 pass