- Add validate_series_key() function that validates URL-safe, lowercase,
hyphen-separated series keys (e.g., 'attack-on-titan')
- Add validate_series_key_or_folder() for backward compatibility during
transition from folder-based to key-based identification
- Create comprehensive test suite with 99 test cases for all validators
- Update infrastructure.md with validation utilities documentation
- Mark Task 4.6 as complete in instructions.md
Test: conda run -n AniWorld python -m pytest tests/unit/test_validators.py -v
All 99 validator tests pass, 718 total unit tests pass
