Add format check CI task (#658)

.github/workflows/format.yaml

@@ -0,0 +1,23 @@
+name: Prettier Check
+
+on:
+  pull_request:
+    branches: [ main, master ]
+
+jobs:
+  prettier:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Use Node.js
+      uses: actions/setup-node@v3
+      with:
+        node-version: lts/*
+
+    - name: Install dependencies
+      run: npm ci
+
+    - name: Run Prettier check
+      run: npx prettier --check './**/*.{js,ts,tsx,vue}'