ci(deps): bump actions/upload-pages-artifact from 4 to 5

Bumps [actions/upload-pages-artifact](https://github.com/actions/upload-pages-artifact) from 4 to 5.
- [Release notes](https://github.com/actions/upload-pages-artifact/releases)
- [Commits](https://github.com/actions/upload-pages-artifact/compare/v4...v5)

---
updated-dependencies:
- dependency-name: actions/upload-pages-artifact
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/deploy-docs.yml

@@ -105,7 +105,7 @@ jobs:
           test -f docs/_build/html/index.html && echo "✓ index.html exists" || echo "✗ index.html missing"
 
       - name: Upload build artifacts
-        uses: actions/upload-pages-artifact@v4
+        uses: actions/upload-pages-artifact@v5
         if: |
           github.event.workflow_run.head_branch == 'main' ||
           (github.event_name == 'workflow_dispatch' && github.event.inputs.deploy_to_pages == 'true')