Add CI workflow for linting and smoke testing

.github/workflows/ci.yml

@@ -0,0 +1,42 @@
+name: CI
+
+on:
+  push:
+    branches: ["main", "dev"]
+  pull_request:
+    branches: ["main"]
+
+jobs:
+  lint-and-build:
+    name: Lint & Smoke Test
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: "npm"
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Check for syntax errors
+        run: node --check main.js
+
+      - name: Verify package.json scripts exist
+        run: |
+          node -e "
+            const pkg = require('./package.json');
+            const required = ['start', 'dist'];
+            for (const s of required) {
+              if (!pkg.scripts?.[s]) {
+                console.error('Missing script:', s);
+                process.exit(1);
+              }
+            }
+            console.log('All required scripts present.');
+          "