Add lint workflow and use yarn

.github/workflows/lint-and-format.yml

@@ -0,0 +1,27 @@
+name: Lint and Format
+
+on:
+  - push
+  - pull_request
+
+jobs:
+  lint-and-format:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 18
+
+      - name: Install packages
+        run: yarn install --frozen-lockfile
+
+      - name: Run ESLint
+        run: yarn lint
+
+      - name: Check Prettier formatting
+        run: yarn format:check

.github/workflows/tests.yml

@@ -18,7 +18,7 @@ jobs:
           node-version: 18
 
       - name: Install packages
-        uses: bahmutov/npm-install@v1
+        run: yarn install --frozen-lockfile
 
       - name: Run tests
-        run: npm run test
+        run: yarn test