feat(exam-homework): add audit report, i18n, error boundaries, and permission hardening

- Add comprehensive audit report for exam and homework module

- Create exam-homework i18n message files (zh-CN + en) and register namespace

- Add permission check to gradeHomeworkSubmissionAction to prevent horizontal privilege escalation

- Add Error Boundary + loading.tsx for 5 key pages (exam build/proctoring, homework assignment/submissions, student assignment)

- Refactor exam-columns to createExamColumns(t) factory for i18n support

- Refactor exam-data-table to manage columns internally via useTranslations

- Replace hardcoded strings with i18n keys in all exam/homework components and pages

- Add getHomeworkSubmissionForGrading data-access for secure grading flow

src/app/(dashboard)/teacher/exams/[id]/build/error.tsx

@@ -0,0 +1,24 @@
+"use client"
+
+import { AlertCircle } from "lucide-react"
+import { useTranslations } from "next-intl"
+
+import { EmptyState } from "@/shared/components/ui/empty-state"
+
+export default function BuildExamError({ reset }: { error: Error & { digest?: string }; reset: () => void }) {
+  const t = useTranslations("examHomework")
+  return (
+    <div className="flex h-full flex-col items-center justify-center space-y-4 p-8">
+      <EmptyState
+        icon={AlertCircle}
+        title={t("exam.error.loadFailed")}
+        description={t("exam.error.notFound")}
+        action={{
+          label: t("common.retry"),
+          onClick: () => reset(),
+        }}
+        className="border-none shadow-none h-auto"
+      />
+    </div>
+  )
+}

src/app/(dashboard)/teacher/exams/[id]/build/loading.tsx

@@ -0,0 +1,16 @@
+import { Skeleton } from "@/shared/components/ui/skeleton"
+
+export default function Loading() {
+  return (
+    <div className="flex h-full flex-col space-y-4 p-4">
+      <div className="space-y-2">
+        <Skeleton className="h-7 w-40" />
+        <Skeleton className="h-4 w-72" />
+      </div>
+      <div className="grid w-full grid-cols-1 gap-4 lg:grid-cols-3">
+        <Skeleton className="h-[600px] lg:col-span-2" />
+        <Skeleton className="h-[600px] lg:col-span-1" />
+      </div>
+    </div>
+  )
+}

src/app/(dashboard)/teacher/exams/[id]/proctoring/error.tsx

@@ -0,0 +1,24 @@
+"use client"
+
+import { AlertCircle } from "lucide-react"
+import { useTranslations } from "next-intl"
+
+import { EmptyState } from "@/shared/components/ui/empty-state"
+
+export default function ProctoringError({ reset }: { error: Error & { digest?: string }; reset: () => void }) {
+  const t = useTranslations("examHomework")
+  return (
+    <div className="flex h-full flex-col items-center justify-center space-y-4 p-8">
+      <EmptyState
+        icon={AlertCircle}
+        title={t("exam.error.loadFailed")}
+        description={t("exam.error.notFound")}
+        action={{
+          label: t("common.retry"),
+          onClick: () => reset(),
+        }}
+        className="border-none shadow-none h-auto"
+      />
+    </div>
+  )
+}

src/app/(dashboard)/teacher/exams/[id]/proctoring/loading.tsx

@@ -0,0 +1,18 @@
+import { Skeleton } from "@/shared/components/ui/skeleton"
+
+export default function Loading() {
+  return (
+    <div className="flex h-full flex-col space-y-4 p-4">
+      <div className="space-y-2">
+        <Skeleton className="h-7 w-48" />
+        <Skeleton className="h-4 w-72" />
+      </div>
+      <div className="grid grid-cols-1 gap-4 md:grid-cols-3">
+        <Skeleton className="h-32" />
+        <Skeleton className="h-32" />
+        <Skeleton className="h-32" />
+      </div>
+      <Skeleton className="h-[500px] w-full" />
+    </div>
+  )
+}

src/app/(dashboard)/teacher/exams/all/page.tsx

@@ -1,12 +1,12 @@
 import type { JSX } from "react"
 import { Suspense } from "react"
 import Link from "next/link"
+import { getTranslations } from "next-intl/server"
 import { Button } from "@/shared/components/ui/button"
 import { Badge } from "@/shared/components/ui/badge"
 import { EmptyState } from "@/shared/components/ui/empty-state"
 import { Skeleton } from "@/shared/components/ui/skeleton"
 import { ExamDataTable } from "@/modules/exams/components/exam-data-table"
-import { examColumns } from "@/modules/exams/components/exam-columns"
 import { ExamFilters } from "@/modules/exams/components/exam-filters"
 import { getExams } from "@/modules/exams/data-access"
 import { getAuthContext } from "@/shared/lib/auth-guard"
@@ -16,6 +16,7 @@ import { FileText, PlusCircle } from "lucide-react"
 async function ExamsResults({ searchParams }: { searchParams: Promise<SearchParams> }): Promise<JSX.Element> {
   const params = await searchParams
   const { dataScope } = await getAuthContext()
+  const t = await getTranslations("examHomework")
 
   const q = getParam(params, "q")
   const status = getParam(params, "status")
@@ -45,20 +46,20 @@ async function ExamsResults({ searchParams }: { searchParams: Promise<SearchPara
     <div className="space-y-4">
       <div className="flex flex-col gap-3 rounded-md border bg-card px-4 py-3 md:flex-row md:items-center md:justify-between">
         <div className="flex flex-wrap items-center gap-2">
-          <span className="text-sm text-muted-foreground">Showing</span>
+          <span className="text-sm text-muted-foreground">{t("exam.list.showing")}</span>
           <span className="text-sm font-medium">{counts.total}</span>
-          <span className="text-sm text-muted-foreground">exams</span>
+          <span className="text-sm text-muted-foreground">{t("exam.list.examsUnit")}</span>
           <Badge variant="outline" className="ml-0 md:ml-2">
-            Draft {counts.draft}
+            {t("exam.status.draft")} {counts.draft}
           </Badge>
-          <Badge variant="outline">Published {counts.published}</Badge>
-          <Badge variant="outline">Archived {counts.archived}</Badge>
+          <Badge variant="outline">{t("exam.status.published")} {counts.published}</Badge>
+          <Badge variant="outline">{t("exam.status.archived")} {counts.archived}</Badge>
         </div>
         <div className="flex items-center gap-2">
           <Button asChild size="sm">
             <Link href="/teacher/exams/create" className="inline-flex items-center gap-2">
               <PlusCircle className="h-4 w-4" aria-hidden="true" />
-              Create Exam
+              {t("exam.list.create")}
             </Link>
           </Button>
         </div>
@@ -67,27 +68,27 @@ async function ExamsResults({ searchParams }: { searchParams: Promise<SearchPara
       {exams.length === 0 ? (
         <EmptyState
           icon={FileText}
-          title={hasFilters ? "No exams match your filters" : "No exams yet"}
+          title={hasFilters ? t("exam.list.emptyFiltered") : t("exam.list.empty")}
           description={
             hasFilters
-              ? "Try clearing filters or adjusting keywords."
-              : "Create your first exam to start assigning and grading."
+              ? t("exam.list.emptyFilteredDescription")
+              : t("exam.list.emptyDescription")
           }
           action={
             hasFilters
               ? {
-                  label: "Clear filters",
+                  label: t("exam.list.clearFilters"),
                   href: "/teacher/exams/all",
                 }
               : {
-                  label: "Create Exam",
+                  label: t("exam.list.create"),
                   href: "/teacher/exams/create",
                 }
           }
           className="h-[360px] bg-card"
         />
       ) : (
-        <ExamDataTable columns={examColumns} data={exams} />
+        <ExamDataTable data={exams} />
       )}
     </div>
   )