refactor(vnt-web): 前端重构为 Vite+Vue3+Pinia 工程并重新设计 UI

- 单文件 index.html 拆分为 vnt-web/ui(pnpm+Vite+Vue3 SFC+Pinia+Tailwind v4),构建产物输出到 static/
- UI 重新设计:浅色简洁风(可切换深色模式)、顶部导航、新增总览仪表盘首页
- 自定义弹窗/toast/确认框替换全部原生 alert/confirm,交互与过渡统一
- 响应式布局:移动端汉堡导航,表格与卡片自适应
- 实例卡片移除日志按钮;启动组网默认选中第一个配置

vnt-web/ui/src/router/index.js

@@ -0,0 +1,21 @@
+import { createRouter, createWebHashHistory } from "vue-router";
+import DashboardView from "../views/DashboardView.vue";
+import InstancesView from "../views/InstancesView.vue";
+import ConfigView from "../views/ConfigView.vue";
+import PeersView from "../views/PeersView.vue";
+import RoutesView from "../views/RoutesView.vue";
+
+const routes = [
+  { path: "/", component: DashboardView },
+  { path: "/instances", component: InstancesView },
+  // 兼容旧路由
+  { path: "/general", redirect: "/instances" },
+  { path: "/config", component: ConfigView },
+  { path: "/peers", component: PeersView },
+  { path: "/routes", component: RoutesView },
+];
+
+export default createRouter({
+  history: createWebHashHistory(),
+  routes,
+});