Add CI workflow

.github/workflows/ci.yml

@@ -0,0 +1,30 @@
+name: CI
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+
+jobs:
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version:
+          - "20.x"
+          - "22.x"
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          cache: pnpm
+      - uses: pnpm/actions-setup@v4
+      - run: pnpm install
+      - name: Build
+        run: pnpm run -w build
+      - name: Test
+        run: pnpm run -w test