Chore(deps-dev): 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:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

pyproject.toml

@@ -126,7 +126,7 @@ optional-dependencies.develop = [
   "validate-pyproject<1",
 ]
 optional-dependencies.doc = [
-  "furo==2025.9.25",               # Check visited link style on newer versions!
+  "furo==2025.12.19",               # Check visited link style on newer versions!
   "myst-parser[linkify]>=0.18,<5",
   "sphinx<8",
   "sphinx-autobuild==2021.3.14",   # Newer versions stopped "watching" appropriately?