fix: 移除安装状态永久缓存，修复数据库重置后无法跳转安装页；优化登录401错误提示

frontend/src/router/index.ts

@@ -75,15 +75,12 @@ const router = createRouter({
   routes,
 })
 
-let installedChecked = false
 let isInstalled = false
 
 async function checkInstalled() {
-  if (installedChecked) return isInstalled
   try {
     const res: any = await systemApi.checkInstalled()
     isInstalled = res.installed
-    installedChecked = true
     return isInstalled
   } catch {
     return true