Build docs with a more recent version of Python

[TimMonko]

🧰 Task

Currently, docs are built with Python 3.11, which is scheduled to be dropped by SPEC0 in Q4 2026.
I propose we build docs on 3.13.

xref napari/napari#8867
xref napari/packaging#370

[Czaki]

@TimMonko Are you sure with python 3.11?

Everywhere I see python 3.12

docs/.circleci/config.yml

Line 37 in 0833d83

- image: cimg/python:3.12.11

https://github.com/napari/shared-workflows/blob/7413dac364a89136618203b559d36926bc81c2c1/.github/workflows/build_docs.yml#L52
https://github.com/napari/napari/blob/71dc7fe23c1d2d295d55fc2280672915dde049e6/.circleci/config.yml#L14

The steeps to migrate.

1. Generate constraints file in napari/napari repo

uv pip compile --python-version 3.13 --output-file resources/constraints/constraints_py3.13_docs.txt pyproject.toml resources/constraints/version_denylist.txt resources/constraints/version_denylist_examples.txt --group docs --extra pyqt6 --extra pyside6 --extra testing --group testing_extra --extra all_optional --exclude resources/constraints/napari_exclude.txt

best on linux
2) update circle.ci configuration in napari/napari repo - this will allow us to test if build pass
3) open PR to (shared-workflows)[https://github.com/napari/shared-workflows] to update github configurations
4) update circle.ci configuration for docs repo.

I do not find yet a way to share circle.ci configuration between repositories, but not dig really deeply.