feat(web): Vitest 测试基建与首批单测（#27）+ 公共格式化函数

web/package.json

@@ -7,6 +7,7 @@
     "dev": "vite",
     "build": "tsc -b && vite build",
     "lint": "oxlint",
+    "test": "vitest run",
     "preview": "vite preview"
   },
   "dependencies": {
@@ -24,12 +25,16 @@
     "react-router-dom": "^7.18.1"
   },
   "devDependencies": {
+    "@testing-library/jest-dom": "^7.0.1",
+    "@testing-library/react": "^16.3.2",
     "@types/node": "^24.13.2",
     "@types/react": "^18.3.27",
     "@types/react-dom": "^18.3.7",
     "@vitejs/plugin-react": "^6.0.3",
+    "jsdom": "^30.0.1",
     "oxlint": "^1.71.0",
     "typescript": "~6.0.2",
-    "vite": "^8.1.1"
+    "vite": "^8.1.1",
+    "vitest": "^4.1.10"
   }
 }