[Feat]: Add linter to the project and to githbub actions

### Is your feature request related to a problem? Please describe.

at minimal "ruff check", it would be great to use also mypy
It needs a pass to fix the various issue lint is finding currently and then activate github action

### Describe the solution you'd like

We need to ensure the format respects the format defined. Add also a note to CONTRIBUTE.md

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

First, run 'ruff check' on the project to see current linting issues. Fix them across the codebase. Then, add a GitHub Actions workflow file (likely in .github/workflows/) to run the linter on push/pull request. Update CONTRIBUTE.md with instructions for contributors to run the linter locally. Verify the action passes after fixes.

Vom Indexierungsmodell aus dem Issue-Text verfasst.