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/dashboard/components/teacher-dashboard/teacher-dashboard-view.tsx

@@ -7,6 +7,7 @@ import { RecentSubmissions } from "./recent-submissions"
 import { TeacherSchedule } from "./teacher-schedule"
 import { TeacherStats } from "./teacher-stats"
 import { TeacherGradeTrends } from "./teacher-grade-trends"
+import { TeacherTodoCard, type TeacherTodoItem } from "./teacher-todo-card"
 
 const toWeekday = (d: Date): 1 | 2 | 3 | 4 | 5 | 6 | 7 => {
   const day = d.getDay()
@@ -32,16 +33,12 @@ export function TeacherDashboardView({ data }: { data: TeacherDashboardData }) {
 
   const submittedSubmissions = data.submissions.filter((s) => Boolean(s.submittedAt))
   const toGradeCount = submittedSubmissions.filter((s) => s.status === "submitted").length
-  
-  // Filter for submissions that actually need grading (status === "submitted")
-  // If we have less than 5 to grade, maybe also show some recently graded ones?
-  // For now, let's stick to "Needs Grading" as it's more useful.
+
   const submissionsToGrade = submittedSubmissions
     .filter(s => s.status === "submitted")
-    .sort((a, b) => new Date(a.submittedAt!).getTime() - new Date(b.submittedAt!).getTime()) // Oldest first? Or Newest? Usually oldest first for queue.
+    .sort((a, b) => (a.submittedAt ? new Date(a.submittedAt).getTime() : 0) - (b.submittedAt ? new Date(b.submittedAt).getTime() : 0))
     .slice(0, 6);
 
-  // Calculate stats for the dashboard
   const activeAssignmentsCount = data.assignments.filter(a => a.status === "published").length
   
   const totalTrendScore = data.gradeTrends.reduce((acc, curr) => acc + curr.averageScore, 0)
@@ -51,6 +48,13 @@ export function TeacherDashboardView({ data }: { data: TeacherDashboardData }) {
   const totalPotentialSubmissions = data.gradeTrends.reduce((acc, curr) => acc + curr.totalStudents, 0)
   const submissionRate = totalPotentialSubmissions > 0 ? (totalSubmissions / totalPotentialSubmissions) * 100 : 0
 
+  // 待办聚合
+  const todoItems: TeacherTodoItem[] = [
+    { label: "待批改作业", count: toGradeCount, href: "/teacher/homework/submissions", variant: toGradeCount > 0 ? "urgent" : "normal" },
+    { label: "今日待考勤", count: todayScheduleItems.length, href: "/teacher/attendance/sheet", variant: "info" },
+    { label: "进行中作业", count: activeAssignmentsCount, href: "/teacher/homework/assignments", variant: "normal" },
+  ]
+
   return (
     <div className="flex h-full flex-col space-y-6 p-8">
       <TeacherDashboardHeader teacherName={data.teacherName} />
@@ -63,18 +67,25 @@ export function TeacherDashboardView({ data }: { data: TeacherDashboardData }) {
       />
 
       <div className="grid gap-6 lg:grid-cols-12">
+        {/* 移动端优先展示：今日课表 → 待办 → 待批改 */}
         <div className="flex flex-col gap-6 lg:col-span-8">
+            <div className="lg:hidden">
+              <TeacherSchedule items={todayScheduleItems} />
+            </div>
+            <TeacherTodoCard items={todoItems} />
             <TeacherGradeTrends trends={data.gradeTrends} />
             <RecentSubmissions 
                 submissions={submissionsToGrade} 
-                title="Needs Grading"
-                emptyTitle="All caught up!"
-                emptyDescription="You have no pending submissions to grade."
+                title="待批改"
+                emptyTitle="全部批改完成！"
+                emptyDescription="暂无待批改的提交。"
             />
         </div>
         
         <div className="flex flex-col gap-6 lg:col-span-4">
-            <TeacherSchedule items={todayScheduleItems} />
+            <div className="hidden lg:block">
+              <TeacherSchedule items={todayScheduleItems} />
+            </div>
             <TeacherHomeworkCard assignments={data.assignments} />
             <TeacherClassesCard classes={data.classes} />
         </div>