Change approach to extra sphinx.

Author: Eli

.github/workflows/build_sphinx.yml

@@ -51,6 +51,16 @@ jobs:
           python scripts/install_extras.py
           micromamba install -y -c conda-forge -c cadwr-dms schimpy
 
+      - name: Install docs extras (pip WITH deps)
+        shell: bash -l {0}
+        env:
+          PIP_NO_INDEX: "0"            # ensure pip can resolve docs deps
+          PIP_NO_BUILD_ISOLATION: "1"  # optional; fine to keep
+        run: |
+          micromamba activate docs
+          # For [project.optional-dependencies].docs:
+          python -m pip install -e .[doc]
+
       - name: Build Sphinx
         shell: bash -l {0}
         env: