feat(exams,homework,parent): V3 审计深度修复 — 批量批改/考试分析/提交反馈/家长视图/移动端优化

V3-5: exam-actions.tsx 集成 useExamHomeworkFeatures hook，按角色控制菜单项可见性
V3-7: 批量批改 — 新增 batchAutoGradeSubmissions data-access + Server Action + HomeworkBatchGradingView 组件
V3-8: 考试分析仪表盘 — 新增 getExamAnalytics stats-service + ExamAnalyticsDashboard 组件 + /teacher/exams/[id]/analytics 路由
V3-9: 提交后即时反馈页 — 新增 HomeworkSubmissionResult 组件 + /student/learning/assignments/[id]/result 路由
V3-11: 家长考试详情 — 新增 ChildExamDetail 组件 + getStudentExamResults data-access + child-detail-panel exams Tab
V3-12: 移动端触控优化 — 题目导航与考试操作按钮 44px 最小触控目标

修复: instrumentation.ts 适配器补全 questionCount/averageScore/overdueCount 字段
修复: exam-homework-port.ts 类型导入对齐 ExamWithQuestionsForHomework
修复: trend-line-chart.tsx 数据类型允许 undefined（classAverage 可选场景）

同步更新 004/005 架构文档

src/modules/homework/components/homework-take-view.tsx

@@ -125,18 +125,23 @@ export function HomeworkTakeView({ assignmentId, initialData }: HomeworkTakeView
 
   const handleStart = async () => {
     setIsBusy(true)
-    const fd = new FormData()
-    fd.set("assignmentId", assignmentId)
-    const res = await startHomeworkSubmissionAction(null, fd)
-    if (res.success && res.data) {
-      setSubmissionId(res.data)
-      setSubmissionStatus("started")
-      toast.success(t("homework.take.startSuccess"))
-      router.refresh()
-    } else {
-      toast.error(res.message || t("homework.take.startFailed"))
+    try {
+      const fd = new FormData()
+      fd.set("assignmentId", assignmentId)
+      const res = await startHomeworkSubmissionAction(null, fd)
+      if (res.success && res.data) {
+        setSubmissionId(res.data)
+        setSubmissionStatus("started")
+        toast.success(t("homework.take.startSuccess"))
+        router.refresh()
+      } else {
+        toast.error(res.message || t("homework.take.startFailed"))
+      }
+    } catch {
+      toast.error(t("homework.take.startFailed"))
+    } finally {
+      setIsBusy(false)
     }
-    setIsBusy(false)
   }
 
   const handleSaveQuestion = async (questionId: string) => {
@@ -156,22 +161,29 @@ export function HomeworkTakeView({ assignmentId, initialData }: HomeworkTakeView
   const handleSubmit = async () => {
     if (!submissionId) return
     setIsBusy(true)
-    // P2-9: 提交前 flush 自动保存队列，确保所有答案已落库
-    await autoSave.flush()
+    try {
+      // P2-9: 提交前 flush 自动保存队列，确保所有答案已落库
+      // flush 失败应中止提交，避免丢失未保存的答案
+      await autoSave.flush()
 
-    const submitFd = new FormData()
-    submitFd.set("submissionId", submissionId)
-    const submitRes = await submitHomeworkAction(null, submitFd)
-    if (submitRes.success) {
-      // 提交成功后清除离线缓存
-      clearOfflineCache(offlineStorageKey)
-      toast.success(t("homework.take.submitSuccess"))
-      setSubmissionStatus("submitted")
-      router.push("/student/learning/assignments")
-    } else {
-      toast.error(submitRes.message || t("homework.take.submitFailed"))
+      const submitFd = new FormData()
+      submitFd.set("submissionId", submissionId)
+      const submitRes = await submitHomeworkAction(null, submitFd)
+      if (submitRes.success) {
+        // 提交成功后清除离线缓存
+        clearOfflineCache(offlineStorageKey)
+        toast.success(t("homework.take.submitSuccess"))
+        setSubmissionStatus("submitted")
+        // V3-9: 提交后跳转到结果页，展示即时反馈
+        router.push(`/student/learning/assignments/${assignmentId}/result`)
+      } else {
+        toast.error(submitRes.message || t("homework.take.submitFailed"))
+      }
+    } catch {
+      toast.error(t("homework.take.submitFailed"))
+    } finally {
+      setIsBusy(false)
     }
-    setIsBusy(false)
   }
 
   // 统计未作答题目数
@@ -378,7 +390,7 @@ export function HomeworkTakeView({ assignmentId, initialData }: HomeworkTakeView
                           if (el) el.scrollIntoView({ behavior: "smooth", block: "start" })
                         }}
                         className={cn(
-                          "h-8 w-8 rounded flex items-center justify-center text-xs font-medium border transition-colors hover:opacity-80 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-1",
+                          "h-11 w-11 sm:h-8 sm:w-8 rounded flex items-center justify-center text-xs font-medium border transition-colors hover:opacity-80 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-1",
                           hasAnswer ? "bg-primary text-primary-foreground border-primary" : "bg-background text-muted-foreground border-input"
                         )}
                         aria-label={t("homework.take.jumpToQuestion", { index: i + 1 })}