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/lesson-preparation/components/publish-homework-dialog.tsx

@@ -3,6 +3,7 @@
 import { useState } from "react";
 import { useTranslations } from "next-intl";
 import { publishLessonPlanHomeworkAction } from "../actions-publish";
+import { useLessonPlanTrackerSafe } from "../providers/lesson-plan-provider";
 import { Button } from "@/shared/components/ui/button";
 import { X } from "lucide-react";
 
@@ -22,6 +23,7 @@ export function PublishHomeworkDialog({
   onPublished,
 }: Props) {
   const t = useTranslations("lessonPreparation");
+  const tracker = useLessonPlanTrackerSafe();
   const [selectedClasses, setSelectedClasses] = useState<string[]>([]);
   const [availableAt, setAvailableAt] = useState("");
   const [dueAt, setDueAt] = useState("");
@@ -44,6 +46,11 @@ export function PublishHomeworkDialog({
     });
     setLoading(false);
     if (res.success) {
+      tracker.track("lesson_plan.publish", {
+        planId,
+        blockId,
+        classCount: selectedClasses.length,
+      });
       onPublished();
       onClose();
     } else {