ENH: build the dev MNE wheel for JupyterLite (JupyterLite split 2/5)

[natinew77-creator]

Part 2 of the split of #13925. Part 1 is #14128.

Adds doc/sphinxext/build_lite_wheel.py, which builds MNE as 9999.0.1 into doc/pypi. The piplite addon picks wheels up from there, so the browser kernel installs the development version rather than the older PyPI release. A CircleCI step runs it once before Sphinx.

Pyodide can ship scipy and matplotlib older than MNE's declared minimums, so the script relaxes those two bounds while building and restores pyproject.toml in a finally block, including when the build fails. numpy is left alone, since MNE requires 2.0 and Pyodide ships 2.x.

Nothing installs the wheel yet. The Sphinx wiring follows in the next PR along with the list of pages that get an "Open in JupyterLite" badge, so badges do not land on pages that cannot run in the browser.

[natinew77-creator]

@teonbrooks PR 2 of the split is up. Thanks!

[teonbrooks]

I noticed that the scipy and matplotlib packages should be compatible with MNE https://pyodide.org/en/stable/usage/packages-in-pyodide.html

do you know what version of Pyodide is being used? it may be that we need to bump the version of jupyterlite, which in terms bumps pyodide-kernel. it looks like the latest version of pyodide-kernel uses the 314 version of pyodide, which is built on 3.14 Python
https://github.com/jupyterlite/pyodide-kernel

[natinew77-creator]

I noticed that the scipy and matplotlib packages should be compatible with MNE https://pyodide.org/en/stable/usage/packages-in-pyodide.html

do you know what version of Pyodide is being used? it may be that we need to bump the version of jupyterlite, which in terms bumps pyodide-kernel. it looks like the latest version of pyodide-kernel uses the 314 version of pyodide, which is built on 3.14 Python https://github.com/jupyterlite/pyodide-kernel

Thanks for flagging. We're on Pyodide 0.29.3 (Python 3.13.2), from
jupyterlite-pyodide-kernel 0.7.2.
It ships scipy 1.14.1 and numpy 2.2.5, both fine for MNE, and
matplotlib 3.8.4, just under 3.9. So you're right on scipy, it never
needed relaxing. Dropped that line, kept matplotlib.

I did try the bump. It builds and loads Pyodide 314.0.1, where
matplotlib is 3.10.8. Since #13925 was verified against 0.29.3
throughout, I'd rather do it as a follow-up. Happy either way.