Bump furo from 2025.9.25 to 2025.12.19

Bumps [furo](https://github.com/pradyunsg/furo) from 2025.9.25 to 2025.12.19.
- [Release notes](https://github.com/pradyunsg/furo/releases)
- [Changelog](https://github.com/pradyunsg/furo/blob/main/docs/changelog.md)
- [Commits](pradyunsg/furo@2025.09.25...2025.12.19)

---
updated-dependencies:
- dependency-name: furo
  dependency-version: 2025.12.19
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

setup.py

@@ -59,7 +59,7 @@
     include_package_data=True,
     zip_safe=False,
     install_requires=[
-        "furo==2025.9.25",
+        "furo==2025.12.19",
         "jinja2>=3,<4",
         "jupysql<0.12",
         "myst-nb<1.4",