fix: resolve linting issues across multiple files

- Remove unused imports (os, Optional, json, List, sys, MagicMock, DebugIssueTool)
- Remove unused variable assignments (safe_file_name)
- Fix f-strings without placeholders
- Reorder imports in test_live_integration.py

utils/git_utils.py

@@ -2,9 +2,8 @@
 Git utilities for finding repositories and generating diffs.
 """
 
-import os
 import subprocess
-from typing import Dict, List, Optional, Tuple
+from typing import Dict, List, Tuple
 from pathlib import Path