Convert .ipynb notebooks to marimo .py files, then export to Jupyer in CI

- https://docs.marimo.io/guides/coming_from/jupyter/
- https://docs.marimo.io/guides/exporting/#export-to-jupyter-notebook

Why marimo? 
- Better git diffs
- Developer experience
- Molab links

Why convert to jupyter?
  - Sphyinx rendering
  - Colab links