Make CI pip indexes explicit with safe diagnostics and sequential fallback

.github/workflows/verify.yml

@@ -4,6 +4,8 @@ jobs:
   verify:
     runs-on: ubuntu-latest
     env:
+      CI_PIP_INDEX_URL: ${{ vars.CI_PIP_INDEX_URL }}
+      CI_PIP_FALLBACK_INDEX_URL: ${{ vars.CI_PIP_FALLBACK_INDEX_URL }}
       DEBIAN_MIRROR: ${{ vars.DEBIAN_MIRROR }}
       DEBIAN_SECURITY_MIRROR: ${{ vars.DEBIAN_SECURITY_MIRROR }}
     steps:
@@ -11,7 +13,8 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: '3.14'
-      - run: python -m pip install -e '.[test]'
+      - name: Install CI dependencies with index diagnostics and fallback
+        run: python scripts/ci-install.py
       - run: python -m ruff check pigway_frame_flow tests scripts
       - run: python -m ruff format --check pigway_frame_flow tests scripts
       - run: python -m mypy pigway_frame_flow
@@ -23,4 +26,7 @@ jobs:
           python scripts/ci-compose-verify.py
       - name: Cleanup isolated Docker resources
         if: always()
-        run: python scripts/ci-compose-verify.py --cleanup
+        run: |
+          if [ -n "${FRAME_FLOW_CI_COMPOSE:-}" ] && [ -f "$FRAME_FLOW_CI_COMPOSE" ]; then
+            python scripts/ci-compose-verify.py --cleanup
+          fi