SWI-11363 ci(playground): publish preflight playground to GitHub Pages

.github/workflows/playground.yml

@@ -0,0 +1,55 @@
+name: Playground
+
+on:
+  push:
+    branches: ["main"]
+  workflow_dispatch:
+
+concurrency:
+  group: pages
+  cancel-in-progress: false
+
+jobs:
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Setup Node
+        uses: actions/setup-node@v6
+        with:
+          node-version: "22"
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build playground
+        run: npm run playground:build
+
+      - name: Stage site
+        run: |
+          mkdir -p _site
+          cp dist/playground.html _site/index.html
+
+      - name: Upload Pages artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: _site
+
+  deploy:
+    name: Deploy
+    needs: build
+    runs-on: ubuntu-latest
+    permissions:
+      pages: write
+      id-token: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4