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/modules/settings/components/settings-view.tsx

@@ -1,19 +1,34 @@
 "use client"
 
 import Link from "next/link"
-import type { ReactNode } from "react"
-import { User, Palette, Lock, Bell } from "lucide-react"
+import { useRouter, useSearchParams } from "next/navigation"
+import { Suspense, type ReactNode } from "react"
+import { User, Palette, Lock, Bell, Sparkles } from "lucide-react"
 import { signOut } from "next-auth/react"
 
 import { ThemePreferencesCard } from "@/modules/settings/components/theme-preferences-card"
 import { ProfileSettingsForm } from "@/modules/settings/components/profile-settings-form"
 import { PasswordChangeForm } from "@/modules/settings/components/password-change-form"
 import { NotificationPreferencesForm } from "@/modules/settings/components/notification-preferences-form"
+import { AiProviderSettingsCard } from "@/modules/settings/components/ai-provider-settings-card"
 import { Button } from "@/shared/components/ui/button"
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/shared/components/ui/card"
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/shared/components/ui/tabs"
+import {
+  AlertDialog,
+  AlertDialogAction,
+  AlertDialogCancel,
+  AlertDialogContent,
+  AlertDialogDescription,
+  AlertDialogFooter,
+  AlertDialogHeader,
+  AlertDialogTitle,
+  AlertDialogTrigger,
+} from "@/shared/components/ui/alert-dialog"
 import { UserProfile } from "@/modules/users/data-access"
 import type { NotificationPreferences } from "@/modules/notifications/types"
+import { usePermission } from "@/shared/hooks/use-permission"
+import { Permissions } from "@/shared/types/permissions"
 
 interface SettingsViewProps {
   /** 页面副标题描述 */
@@ -28,24 +43,52 @@ interface SettingsViewProps {
   generalExtra?: ReactNode
 }
 
+const VALID_TABS = ["general", "notifications", "appearance", "security", "ai"] as const
+type TabValue = (typeof VALID_TABS)[number]
+
+function isTabValue(value: string | null): value is TabValue {
+  return value !== null && (VALID_TABS as readonly string[]).includes(value)
+}
+
 /**
  * 统一设置页视图
  *
- * 消除 admin / teacher / student 三个设置视图的重复布局：
+ * 消除 admin / teacher / student / parent 四个设置视图的重复布局：
  * - 相同的页面头部（标题 + 描述 + 返回按钮）
- * - 相同的 4 个标签页（General / Notifications / Appearance / Security）
+ * - 相同的标签页（General / Notifications / Appearance / Security / AI）
  * - 相同的 Notifications / Appearance / Security 标签页内容
  * - 相同的 Session 卡片（登出）
  *
  * 角色差异通过 `description`、`backHref` 和 `generalExtra` 三个 props 注入。
+ * 当前激活的标签页通过 URL `?tab=` 参数持久化。
  */
-export function SettingsView({
+function SettingsViewInner({
   description,
   backHref,
   user,
   notificationPreferences,
   generalExtra,
 }: SettingsViewProps) {
+  const router = useRouter()
+  const searchParams = useSearchParams()
+  const { hasPermission } = usePermission()
+
+  const tabParam = searchParams.get("tab")
+  const activeTab: TabValue = isTabValue(tabParam) ? tabParam : "general"
+
+  const handleTabChange = (value: string) => {
+    const params = new URLSearchParams(searchParams.toString())
+    if (value === "general") {
+      params.delete("tab")
+    } else {
+      params.set("tab", value)
+    }
+    const query = params.toString()
+    router.push(query ? `?${query}` : "?", { scroll: false })
+  }
+
+  const canConfigureAi = hasPermission(Permissions.AI_CONFIGURE)
+
   return (
     <div className="flex h-full flex-col gap-8 p-8">
       <div className="flex flex-col justify-between gap-4 md:flex-row md:items-center">
@@ -60,7 +103,7 @@ export function SettingsView({
         </div>
       </div>
 
-      <Tabs defaultValue="general" className="w-full">
+      <Tabs value={activeTab} onValueChange={handleTabChange} className="w-full">
         <TabsList className="w-full justify-start">
           <TabsTrigger value="general" className="gap-2">
             <User className="h-4 w-4" />
@@ -78,6 +121,12 @@ export function SettingsView({
             <Lock className="h-4 w-4" />
             Security
           </TabsTrigger>
+          {canConfigureAi ? (
+            <TabsTrigger value="ai" className="gap-2">
+              <Sparkles className="h-4 w-4" />
+              AI
+            </TabsTrigger>
+          ) : null}
         </TabsList>
 
         <TabsContent value="general" className="mt-6 space-y-6">
@@ -105,13 +154,43 @@ export function SettingsView({
                 <div className="text-sm font-medium">Sign out</div>
                 <div className="text-sm text-muted-foreground">Return to the login screen.</div>
               </div>
-              <Button variant="outline" onClick={() => signOut({ callbackUrl: "/login" })}>
-                Log out
-              </Button>
+              <AlertDialog>
+                <AlertDialogTrigger asChild>
+                  <Button variant="outline">Log out</Button>
+                </AlertDialogTrigger>
+                <AlertDialogContent>
+                  <AlertDialogHeader>
+                    <AlertDialogTitle>Confirm sign out</AlertDialogTitle>
+                    <AlertDialogDescription>
+                      Are you sure you want to sign out? You will be returned to the login screen.
+                    </AlertDialogDescription>
+                  </AlertDialogHeader>
+                  <AlertDialogFooter>
+                    <AlertDialogCancel>Cancel</AlertDialogCancel>
+                    <AlertDialogAction onClick={() => signOut({ callbackUrl: "/login" })}>
+                      Sign out
+                    </AlertDialogAction>
+                  </AlertDialogFooter>
+                </AlertDialogContent>
+              </AlertDialog>
             </CardContent>
           </Card>
         </TabsContent>
+
+        {canConfigureAi ? (
+          <TabsContent value="ai" className="mt-6 space-y-6">
+            <AiProviderSettingsCard />
+          </TabsContent>
+        ) : null}
       </Tabs>
     </div>
   )
 }
+
+export function SettingsView(props: SettingsViewProps) {
+  return (
+    <Suspense fallback={null}>
+      <SettingsViewInner {...props} />
+    </Suspense>
+  )
+}