Add CI workflow

.github/workflows/ci.yml

@@ -0,0 +1,36 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  ci:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - uses: pnpm/action-setup@v3
+        name: Set up pnpm
+        with:
+          version: latest
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Build
+        run: pnpm build
+
+      - name: Run tests
+        run: pnpm test:ci
+
+      - uses: codecov/codecov-action@v4
+        with:
+          use_oidc: true