Add 'lint' script to package.json

- 'vue-tsc' uses '--build' because we are using 'references' in
  tsconfig.json.
- 'vue-tsc' doesn't use '--noEmit' because it is incompatible with
  '--build'. Instead we set 'noEmit' to 'true' in the referenced
  tsconfig.json files.
- 'vue-tsc' uses '--force' to make check-only builds more reliable (see
  vuejs/create-vue#274).

frontend/package.json

@@ -6,7 +6,8 @@
   "scripts": {
     "dev": "vite",
     "build": "vite build",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "lint": "vue-tsc --build --force"
   },
   "devDependencies": {
     "@types/node": "^20.11.20",