fix: align playground workflow with GitHub Pages template

Add configure-pages action and set cancel-in-progress to false
to avoid interrupting production deployments.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Mazyod

.github/workflows/playground.yml

@@ -15,7 +15,7 @@ permissions:
 
 concurrency:
   group: "pages"
-  cancel-in-progress: true
+  cancel-in-progress: false
 
 jobs:
   build:
@@ -32,6 +32,9 @@ jobs:
           cache: npm
           cache-dependency-path: playground/package-lock.json
 
+      - name: Setup Pages
+        uses: actions/configure-pages@v5
+
       - run: npm ci
       - run: npm run build