- Add comprehensive tests for all packages (3572 tests, 100% branch coverage)
- Split oversized test files to stay under 500-line limit
- Add per-file ruff ignores for test-appropriate suppressions
- Fix _cache_decks.py to properly convert JSON lists to tuples
- Add session-scoped conftest fixture for logging handler cleanup (Python 3.14)
- Update ruff pre-commit hook to v0.15.2
- Add codespell ignore words for test data
- Add generated output files to .gitignore
- Replace print() with logging module
- Add type annotations to all functions
- Add Google-style docstrings to all public functions/classes
- Extract magic numbers into named constants
- Break complex functions into smaller helpers
- Use Path.open() instead of open()
- Use contextlib.suppress where appropriate