Add CI: tests and static analysis on push/PR

.github/workflows/ci.yml

@@ -0,0 +1,60 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+# Cancel superseded runs on the same ref to save CI minutes.
+concurrency:
+  group: ci-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  static-analysis:
+    name: Static analysis
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Type-check (tsc --noEmit, strict)
+        run: npm run typecheck
+
+      - name: Generated types are in sync with the schema
+        run: |
+          npm run gen
+          if ! git diff --exit-code -- src/generated; then
+            echo "::error::src/generated is out of date. Run 'npm run gen' and commit the result."
+            exit 1
+          fi
+
+  test:
+    name: Tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run tests (vitest)
+        run: npm test