Test the editor with Vitest: grid and top bar rules, the store, and the components in jsdom

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

web/package.json

@@ -7,15 +7,20 @@
     "dev": "vite",
     "build": "rm -rf ../screen_manager/app/static/assets && vite build",
     "check": "vue-tsc --noEmit",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "test": "vitest run",
+    "test:watch": "vitest"
   },
   "dependencies": {
     "vue": "^3.5.18"
   },
   "devDependencies": {
     "@vitejs/plugin-vue": "^6.0.1",
+    "@vue/test-utils": "^2.5.1",
+    "jsdom": "^26.1.0",
     "typescript": "^5.9.2",
     "vite": "^7.1.5",
+    "vitest": "^3.2.7",
     "vue-tsc": "^3.0.6"
   }
 }