fix(dashboard): v3 审计修复 — 数据完整性、i18n、类型安全、死代码清理

P0 修复（严重）:
- admin ContentRow 标签与值错配（stats.users→textbooks 等 6 处）
- admin/error.tsx 硬编码中文替换为 useTranslations
- UserGrowthChart 空数据时渲染 EmptyState（userGrowth/homeworkTrend 永远为空数组）

P1 修复（高）:
- 新增 admin/dashboard 和 student/dashboard 的 loading.tsx + error.tsx
- 抽取 DashboardLoadingSkeleton 和 DashboardErrorFallback 共享组件，消除 5 套重复文件
- formatDate/formatLongDate 传入用户 locale（admin/teacher/student 共 6 个组件）
- 移除死代码：getCachedAdminDashboard、AvatarImage src={undefined}、TeacherStats isLoading prop
- filterTodaySchedule 改为泛型函数，消除 as 类型断言
- 辅助函数 getStatus/getDueUrgency 新增显式返回类型
- UserGrowthChart 新增 labelKey prop 区分用户增长/作业提交趋势标签

P2 修复（中）:
- 4 个组件从客户端转为服务端组件（DashboardGreetingHeader、TeacherQuickActions、TeacherDashboardHeader、StudentDashboardHeader）
- Student dashboard 空状态新增 CTA（viewSchedule、viewAll）
- TeacherHomeworkCard 图标按钮新增 aria-label
- TeacherTodoCard 排序逻辑重写为可读的 if/return 模式

同步更新:
- docs/architecture/005_architecture_data.json 新增 DashboardLoadingSkeleton、DashboardErrorFallback 条目
- 新增 docs/architecture/audit/dashboard-audit-report-v3.md 审计报告
- dashboard.json 新增 6 个 i18n 键（textbooks/chapters/questions/exams/totalAssignments/totalSubmissions）

src/modules/parent/components/child-homework-summary.tsx

@@ -4,37 +4,14 @@ import { PenTool, TriangleAlert } from "lucide-react"
 import { Badge } from "@/shared/components/ui/badge"
 import { Card, CardContent, CardHeader, CardTitle } from "@/shared/components/ui/card"
 import { EmptyState } from "@/shared/components/ui/empty-state"
+import { StatusBadge } from "@/shared/components/ui/status-badge"
 import { cn, formatDate } from "@/shared/lib/utils"
-import type { StudentHomeworkProgressStatus } from "@/modules/homework/types"
+import {
+  STUDENT_HOMEWORK_PROGRESS_VARIANT,
+  STUDENT_HOMEWORK_PROGRESS_LABEL,
+} from "@/modules/homework/types"
 import type { ChildHomeworkSummaryData } from "@/modules/parent/types"
 
-const getStatusVariant = (
-  status: StudentHomeworkProgressStatus,
-): "default" | "secondary" | "outline" => {
-  switch (status) {
-    case "graded":
-      return "default"
-    case "submitted":
-    case "in_progress":
-      return "secondary"
-    case "not_started":
-      return "outline"
-  }
-}
-
-const getStatusLabel = (status: StudentHomeworkProgressStatus): string => {
-  switch (status) {
-    case "graded":
-      return "Graded"
-    case "submitted":
-      return "Submitted"
-    case "in_progress":
-      return "In progress"
-    case "not_started":
-      return "Not started"
-  }
-}
-
 type DueUrgency = "overdue" | "urgent" | "normal"
 
 const getDueUrgency = (dueAt: string | null, now: Date): DueUrgency | null => {
@@ -63,7 +40,7 @@ export function ChildHomeworkSummary({
     <Card>
       <CardHeader>
         <CardTitle className="flex items-center gap-2 text-base">
-          <PenTool className="h-4 w-4 text-muted-foreground" />
+          <PenTool className="h-4 w-4 text-muted-foreground" aria-hidden />
           {childName}&apos;s Homework
         </CardTitle>
       </CardHeader>
@@ -83,7 +60,7 @@ export function ChildHomeworkSummary({
           </div>
           <div className="rounded-md bg-muted/50 p-2">
             <div className="text-xs text-muted-foreground flex items-center justify-center gap-1">
-              <TriangleAlert className="h-3 w-3" />
+              <TriangleAlert className="h-3 w-3" aria-hidden />
               Overdue
             </div>
             <div
@@ -112,18 +89,29 @@ export function ChildHomeworkSummary({
             {summary.recentAssignments.map((a) => {
               const urgency = getDueUrgency(a.dueAt, now)
               const isGraded = a.progressStatus === "graded"
+              const scoreText = a.latestScore !== null ? `${a.latestScore} pts` : isGraded ? "Graded" : "-"
               return (
                 <Link
                   key={a.id}
                   href={`/parent/children/${childId}?tab=homework`}
-                  className="flex items-center justify-between rounded-md border bg-card p-3 hover:bg-muted/50 transition-colors"
+                  className="flex min-h-[44px] items-center justify-between rounded-md border bg-card p-3 hover:bg-muted/50 transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2"
                 >
                   <div className="min-w-0 flex-1 space-y-1">
-                    <div className="font-medium text-sm truncate">{a.title}</div>
+                    <div className="flex items-center gap-2">
+                      {a.subjectName ? (
+                        <Badge variant="outline" className="text-[10px] shrink-0">
+                          {a.subjectName}
+                        </Badge>
+                      ) : null}
+                      <div className="font-medium text-sm truncate">{a.title}</div>
+                    </div>
                     <div className="flex items-center gap-2 text-xs text-muted-foreground">
-                      <Badge variant={getStatusVariant(a.progressStatus)} className="text-[10px]">
-                        {getStatusLabel(a.progressStatus)}
-                      </Badge>
+                      <StatusBadge
+                        status={a.progressStatus}
+                        variantMap={STUDENT_HOMEWORK_PROGRESS_VARIANT}
+                        labelMap={STUDENT_HOMEWORK_PROGRESS_LABEL}
+                        className="text-[10px]"
+                      />
                       {a.dueAt ? (
                         <span
                           className={cn(
@@ -136,14 +124,14 @@ export function ChildHomeworkSummary({
                     </div>
                   </div>
                   <div className="text-sm font-medium tabular-nums shrink-0 ml-2">
-                    {a.latestScore ?? "-"}
+                    {scoreText}
                   </div>
                 </Link>
               )
             })}
             <Link
               href={`/parent/children/${childId}?tab=homework`}
-              className="block text-center text-xs text-muted-foreground hover:text-foreground transition-colors pt-1"
+              className="block text-center text-xs text-muted-foreground hover:text-foreground transition-colors pt-1 min-h-[36px] flex items-center justify-center"
             >
               View all
             </Link>