fix tests

feat(tests): add new test files and improve coverage support

- Introduced `PipelineExecutorTest.php` and `ProcessPipelineJobTest.php` for enhanced testing.
- Updated `composer.json` to include a command for generating HTML test coverage reports.
- Fixed a minor issue in `LogNotifier.php` by adjusting the usage of the `getMeta` method.
- Refactored `PipelineHistoryRecorderTest.php` to clean up unused imports and improve readability.