(chore)react-widget: build, publish act

.github/workflows/react-widget-build.yml

@@ -0,0 +1,34 @@
+name: React Widget Build
+
+on:
+  push:
+    paths:
+      - 'extensions/react-widget/**'
+  pull_request:
+    paths:
+      - 'extensions/react-widget/**'
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: extensions/react-widget
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+          cache-dependency-path: extensions/react-widget/package-lock.json
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build
+        run: npm run build