This PR adds several code quality improvements, which basically come down to:

• Explicit return type definitions for every function
• Formatted according to the ruff standard.
• Static type checking with pyright

To enforce code quality going forward, pre-commit hooks for both are included. In case that it is preferable to enforce this, there's github actions available to sync this directly.

Please let me know what you think, and if this is in line with the philosophy of this project.