fix: 添加安装路由，修复环境变量校验和路由守卫

- 注册/install路由，安装向导页面可访问
- env.ts: VITE_SERVER_API_URL默认空字符串(相对路径)
- 路由守卫: API失败时默认跳转安装页面

frontend/src/router/guard/index.ts

@@ -8,14 +8,14 @@ async function checkInstallStatus(): Promise<boolean> {
   try {
     const res = await fetch('/api/install/status')
     const data = await res.json()
-    isInstalled = data?.data?.installed || false
+    isInstalled = data?.data?.installed ?? false
     installChecked = true
     return isInstalled
   }
   catch {
     installChecked = true
-    isInstalled = true
-    return true
+    isInstalled = false
+    return false
   }
 }
 

frontend/src/router/routes.ts

@@ -1,6 +1,15 @@
 import type { RouteRecordRaw } from 'vue-router'
 
 const routes: RouteRecordRaw[] = [
+  {
+    path: '/install',
+    name: 'Install',
+    component: () => import('@/pages/install/index.vue'),
+    meta: {
+      title: '安装 - 管理平台',
+      layout: false,
+    },
+  },
   {
     path: '/',
     redirect: '/login',

frontend/src/utils/env.ts

@@ -9,10 +9,8 @@ import { z } from 'zod'
  */
 
 const EnvSchema = z.object({
-  // Add your environment variables here, for example:
-  // VITE_API_BASE_URL: z.string().url(),
-  VITE_SERVER_API_URL: z.url(),
-  VITE_SERVER_API_PREFIX: z.string(),
+  VITE_SERVER_API_URL: z.string().default(''),
+  VITE_SERVER_API_PREFIX: z.string().default('/api'),
   VITE_SERVER_API_TIMEOUT: z.coerce.number().default(5000),
 })