chore: 添加 Vercel 部署配置

- 配置 vercel.json 用于优化部署
- 设置路由重写规则支持 React Router

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

vercel.json

@@ -0,0 +1,12 @@
+{
+  "buildCommand": "npm run build",
+  "outputDirectory": "build",
+  "devCommand": "npm start",
+  "framework": "create-react-app",
+  "rewrites": [
+    {
+      "source": "/(.*)",
+      "destination": "/index.html"
+    }
+  ]
+}