Setup nbstripout for Easier Code Review

Per Claude/Gemini recommendation. Some instructions below:

```sh
# Install
pip install nbstripout

# Set up for your repo
nbstripout --install

# Or globally
nbstripout --install --global
```


Can also edit the `.gitattributes` manually

```
*.ipynb filter=nbstripout
*.ipynb diff=ipynb
```