Use env.GITHUB_WORKSPACE for container job artifact paths

For jobs running inside containers (container: directive), use
${{ env.GITHUB_WORKSPACE }} instead of ${{ github.workspace }}.

The context variable github.workspace contains the HOST path,
while the environment variable GITHUB_WORKSPACE is set correctly
inside the container.

Rule:
- Outside containers: use ${{ github.workspace }}
- Inside containers: use ${{ env.GITHUB_WORKSPACE }}

Note: This work was completed with AI assistance (Claude Code).

Author: oberstet

.github/workflows/wheels-docker.yml

@@ -475,12 +475,14 @@ jobs:
           echo "==> Wheel inventory:"
           find wheelhouse/ -name "*.whl" -exec basename {} \; 2>/dev/null | sort || echo "No wheels found"
 
+      # Note: For container jobs, use $GITHUB_WORKSPACE (environment variable set inside
+      # the container) instead of ${{ github.workspace }} (context variable with host path).
       - name:
           Upload wheels, source dist and build metadata with cryptographic verification
         uses: wamp-proto/wamp-cicd/actions/upload-artifact-verified@main
         with:
           name: artifacts-${{ matrix.target.name }}
-          path: ${{ github.workspace }}/wheelhouse/
+          path: ${{ env.GITHUB_WORKSPACE }}/wheelhouse/
           retention-days: 30
 
   # GitHub Releases, PyPI, and RTD publishing are now handled by the centralized 'release' workflow