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/unified_synonym_processor.py

@@ -8,9 +8,8 @@
 import sys
 import json
 import argparse
-from typing import Dict, List, Optional, Any, Set
+from typing import Dict, List, Optional, Any
 from pathlib import Path
-import re
 
 
 class UnifiedSynonymProcessor:
@@ -64,11 +63,11 @@ class UnifiedSynonymProcessor:
                 return False
 
         if data.get("format") != "unified_multilingual":
-            print(f"錯誤: 格式必須為 'unified_multilingual'", file=sys.stderr)
+            print("錯誤: 格式必須為 'unified_multilingual'", file=sys.stderr)
             return False
 
         if not isinstance(data["synonym_groups"], list):
-            print(f"錯誤: synonym_groups 必須是列表", file=sys.stderr)
+            print("錯誤: synonym_groups 必須是列表", file=sys.stderr)
             return False
 
         # 驗證每個同義詞組
@@ -377,7 +376,7 @@ def main():
             }
             print(json.dumps(result, ensure_ascii=False, indent=2))
         else:
-            print(f"跨語言同義詞映射")
+            print("跨語言同義詞映射")
             print(f"術語數量: {len(cross_mapping)}")
             print("\n映射:")
             for term, synonyms in list(cross_mapping.items())[:10]:  # 只顯示前10個
@@ -415,7 +414,7 @@ def main():
                     print(f"   語言: {group['language']}")
 
                     if group.get("is_primary"):
-                        print(f"   匹配類型: 主要術語")
+                        print("   匹配類型: 主要術語")
                     elif "matched_synonym" in group:
                         print(f"   匹配類型: 同義詞 ({group['matched_synonym']})")
                     elif "matched_translation" in group: