fix: patch P0 security vulnerabilities and critical UX issues across 6 modules

Security: Add admin/layout.tsx auth guard; Add requirePermission() to 12 admin pages

Dashboard: Fix StudentStatsGrid rendering; Fix teacher greeting; Add loading/error boundaries; Fix col-span; Add metadata

Announcements: Fix audience filtering; Add user detail page; Trigger notifications on publish; Pass classes data; Add loading.tsx

Messages: Implement soft delete; Add unread badge with polling; Add notification dropdown polling; Add keyword search; Add quiet hours DND

Management: Add loading/error for 9 admin routes; Fix admin-classes-view to use Select for school/grade

Profile/Settings: Add loading/error; Fix parent role routing; Create ParentSettingsView; Integrate AiProviderSettingsCard; Add Tab URL persistence; Add logout confirm; Add avatar; Fix Progress arbitrary class

Schema: Add senderDeletedAt/receiverDeletedAt to messages; Add quietHours to notificationPreferences; Add uniqueIndex import

Docs: Update architecture docs 004/005

src/app/(dashboard)/admin/users/import/error.tsx

@@ -0,0 +1,22 @@
+"use client"
+
+import { AlertCircle } from "lucide-react"
+
+import { EmptyState } from "@/shared/components/ui/empty-state"
+
+export default function AdminUsersImportError({ reset }: { error: Error & { digest?: string }; reset: () => void }) {
+  return (
+    <div className="flex h-full flex-col items-center justify-center space-y-4 p-8">
+      <EmptyState
+        icon={AlertCircle}
+        title="页面加载失败"
+        description="抱歉，页面加载时发生了意外错误。请稍后重试。"
+        action={{
+          label: "重试",
+          onClick: () => reset(),
+        }}
+        className="border-none shadow-none h-auto"
+      />
+    </div>
+  )
+}

src/app/(dashboard)/admin/users/import/loading.tsx

@@ -0,0 +1,24 @@
+import { Card, CardContent, CardHeader } from "@/shared/components/ui/card"
+import { Skeleton } from "@/shared/components/ui/skeleton"
+
+export default function AdminUsersImportLoading() {
+  return (
+    <div className="flex h-full flex-col space-y-8 p-8">
+      <div className="space-y-2">
+        <Skeleton className="h-8 w-48" />
+        <Skeleton className="h-4 w-64" />
+      </div>
+
+      <Card>
+        <CardHeader>
+          <Skeleton className="h-5 w-32" />
+        </CardHeader>
+        <CardContent className="space-y-3">
+          {Array.from({ length: 6 }).map((_, i) => (
+            <Skeleton key={i} className="h-12 w-full" />
+          ))}
+        </CardContent>
+      </Card>
+    </div>
+  )
+}

src/app/(dashboard)/admin/users/import/page.tsx

@@ -3,6 +3,8 @@ import type { JSX } from "react"
 import Link from "next/link"
 import { ArrowLeft, Users, FileSpreadsheet, Info } from "lucide-react"
 
+import { requirePermission } from "@/shared/lib/auth-guard"
+import { Permissions } from "@/shared/types/permissions"
 import { Button } from "@/shared/components/ui/button"
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/shared/components/ui/card"
 import {
@@ -22,7 +24,8 @@ export const metadata: Metadata = {
 
 export const dynamic = "force-dynamic"
 
-export default function UserImportPage(): JSX.Element {
+export default async function UserImportPage(): Promise<JSX.Element> {
+  await requirePermission(Permissions.USER_MANAGE)
   return (
     <div className="h-full flex-1 flex-col space-y-6 p-8 md:flex">
       <div className="flex items-center justify-between space-y-2">