- Add _get_effective_path() helper to deduplicate path resolution logic
between list_files and get_file_count methods
- Add broader exception handling in write_file to clean up storage files
when create_workspace_file fails with non-UniqueViolationError errors
- Fix test mock to include required graph_version attribute
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>