- Introduced `quick_test.py` for running specific test categories (unit, integration, theme, all).
- Updated `run_tests.py` to improve test execution and reporting, including coverage.
- Removed outdated test scripts for keyboard shortcuts, menu theming, note saving, and entry updating.
- Added new test script `test_theme_changing.py` to verify theme changing functionality.
- Consolidated integration tests into `test_integration.py` for comprehensive testing of TheChart application.
- Updated theme manager to ensure color retrieval works correctly.
- Modified test constants to import from the correct module path.
