Add code formatting workflow to CI

[simon-jonas-buehrer]

Summary

Our repository currently lacks an automated code formatting check. To maintain consistent code style and simplify reviews, we should add a dedicated GitHub Actions workflow that runs formatting tools (black and isort) automatically.

Tasks

• Create a new workflow file: .github/workflows/format.yml
• Configure it to run on push and pull_request events
• Install and run:

  pip install black isort
  black --check .
  isort --check-only .

• (Optional) Add a separate “auto-fix” job or pre-commit hook if we want automatic formatting
• Document formatting usage in CONTRIBUTING.md

Acceptance Criteria

• Workflow creates warning but does not fail if any file is not properly formatted
• Developers can run black . && isort . locally to fix issues
• Formatting is enforced consistently across PRs

Additional context

This will keep code reviews focused on logic rather than style and ensure consistency with Python best practices.