:chore: Add Node ≥18.16.0 engine requirement and confirm CI setup (#2230)

Author: KATO-Hiro

package.json

@@ -95,5 +95,8 @@
     "vercel": "44.4.1",
     "xss": "1.0.15"
   },
-  "packageManager": "[email protected]"
+  "packageManager": "[email protected]",
+  "engines": {
+    "node": ">=18.16.0"
+  }
 }