Fix CS warnings/errors for GitLab CI pipelines

MR created following the issue description plan
- Update the GitLab CI Setup - Do not allow code with CS errors
- Fix PHPCS issues
- Fix PHPStan issues
- Fix Cspell issues

However there still some issue with PHPStan from AI.
I created an issue there
https://www.drupal.org/project/ai/issues/3505528 🐛 PHPStan Issues - from methods docs vars "typos" - Parameter x of method y has invalid type - Drupal\ai\Operation\zzzz. Active and also provided a MR for those things.

Till that issue is solved ... we could let PHPStan allow the errors ... not to block other issues and the progress on this module
And also have a "cleaner/standard" code.

Automatically closed - issue fixed for 2 weeks with no activity.