Add tmate to docs workflow for debugging

.github/workflows/docs.yaml

@@ -48,6 +48,9 @@ jobs:
         run: pkgdown::build_site_github_pages(new_process = FALSE, install = FALSE)
         shell: Rscript {0}
 
+      - name: Setup tmate session
+        uses: mxschmitt/action-tmate@v3
+
       - name: Build Python docs
         run: uv run sphinx-build python/docs/source docs/python
         shell: bash