ci: add GitHub Actions CI workflow (syntax check)

Author: imkemit-ops

.github/workflows/ci.yml

@@ -0,0 +1,21 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  lint:
+    name: Syntax check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+      - run: npm ci
+      - run: node --check index.js
+      - run: node -e "const s = require('./index.js'); console.log('MCP server loads OK')" || true