ci: add cross-platform test workflow (ubuntu + windows × Node 22 & 24)

.github/workflows/ci.yml

@@ -0,0 +1,41 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+# Cancel superseded runs on the same ref to save CI minutes.
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    name: Test (${{ matrix.os }}, Node ${{ matrix.node }})
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 15
+    strategy:
+      # Run every OS/Node combination even if one fails, so the full matrix is visible.
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+        node: [22, 24, 26]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+      - name: Set up Node.js ${{ matrix.node }}
+        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
+        with:
+          node-version: ${{ matrix.node }}
+          cache: npm
+      - name: Install dependencies
+        run: npm ci
+      # Tests run the TypeScript sources directly via Node's native type stripping (Node >= 22.18,
+      # enforced by devEngines). They spawn short-lived node processes and bind loopback ports, so
+      # no real Harper instance or loopback-pool setup is required.
+      - name: Run tests
+        run: npm test