Clean up backup and debugging files

[djdarcy]

Cleanup Task

Remove or properly organize temporary files created during Issue #17 investigation.

Files to Handle

• folder_datetime_fix/cache_old.py.backup - Backup from cache refactoring
• Various debugging scripts in tests/one-offs/ that are now documented

Recommendation

1. Delete cache_old.py.backup if no longer needed
2. Keep debugging scripts in tests/one-offs/ as they document the investigation process
3. Ensure pytest.ini continues to exclude one-offs from test runs

Notes

These files were created during the investigation and fix of Issue #17 (cache depth limitations). The debugging scripts have been annotated with their relationship to Issue #17 and should be preserved for historical reference.