Add check that it is gh-pages branch

.github/workflows/ci-delete-pr-preview.yml

@@ -29,6 +29,15 @@ jobs:
         run: |
           git config user.name "github-actions[bot]"
           git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+
+          CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
+          echo "Current branch: $CURRENT_BRANCH"
+
+          if [ "$CURRENT_BRANCH" != "gh-pages" ]; then
+            echo "❌ Refusing to force-push to non-gh-pages branch: $CURRENT_BRANCH"
+            exit 1
+          fi
+
           if git diff --cached --quiet; then
             echo "No changes to commit"
           else