chore(yaml): enforce .yaml extension and prefer double quotes in YAML via eslint-plugin-yml; fix rule name; format repo

.github/workflows/format-check.yaml

@@ -0,0 +1,42 @@
+name: format-check
+
+"on":
+  pull_request:
+    branches: ["**"]
+
+jobs:
+  prettier:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: "20"
+          cache: "npm"
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Prettier format check
+        run: npm run format:check
+
+  eslint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: "20"
+          cache: "npm"
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: ESLint
+        run: npm run lint