ci: add GitHub Pages deploy workflow

Author: tai5863

.github/workflows/pages.yml

@@ -0,0 +1,44 @@
+name: Deploy demo to GitHub Pages
+
+on:
+  push:
+    branches: [main]
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - run: npm ci
+      - run: npm run build
+
+      - name: Prepare pages
+        run: |
+          mkdir _site
+          cp demo.html _site/index.html
+          cp -r dist _site/dist
+
+      - uses: actions/configure-pages@v5
+
+      - uses: actions/upload-pages-artifact@v3
+
+      - id: deployment
+        uses: actions/deploy-pages@v4