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

tests/test_review_pending_changes.py

@@ -3,7 +3,7 @@ Tests for the review_pending_changes tool
 """
 
 import json
-from unittest.mock import MagicMock, Mock, patch
+from unittest.mock import Mock, patch
 
 import pytest