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/modules/homework/components/homework-assignment-form.tsx

@@ -5,6 +5,8 @@ import { useFormStatus } from "react-dom"
 import { toast } from "sonner"
 import { useRouter } from "next/navigation"
 import { useSearchParams } from "next/navigation"
+import { useTranslations } from "next-intl"
+import { FileText, FileQuestion } from "lucide-react"
 
 import { Card, CardContent, CardFooter, CardHeader, CardTitle } from "@/shared/components/ui/card"
 import { Button } from "@/shared/components/ui/button"
@@ -12,6 +14,7 @@ import { Input } from "@/shared/components/ui/input"
 import { Label } from "@/shared/components/ui/label"
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/shared/components/ui/select"
 import { Textarea } from "@/shared/components/ui/textarea"
+import { cn } from "@/shared/lib/utils"
 
 import { createHomeworkAssignmentAction } from "../actions"
 import type { TeacherClass } from "@/modules/classes/types"
@@ -20,9 +23,10 @@ type ExamOption = { id: string; title: string }
 
 function SubmitButton() {
   const { pending } = useFormStatus()
+  const t = useTranslations("examHomework")
   return (
     <Button type="submit" disabled={pending}>
-      {pending ? "Creating..." : "Create Assignment"}
+      {pending ? t("homework.form.submitting") : t("homework.form.submit")}
     </Button>
   )
 }
@@ -30,7 +34,9 @@ function SubmitButton() {
 export function HomeworkAssignmentForm({ exams, classes }: { exams: ExamOption[]; classes: TeacherClass[] }) {
   const router = useRouter()
   const searchParams = useSearchParams()
+  const t = useTranslations("examHomework")
 
+  const [mode, setMode] = useState<"exam" | "quick">(exams.length > 0 ? "exam" : "quick")
   const initialExamId = useMemo(() => exams[0]?.id ?? "", [exams])
   const [examId, setExamId] = useState<string>(initialExamId)
   const initialClassId = useMemo(() => {
@@ -40,43 +46,100 @@ export function HomeworkAssignmentForm({ exams, classes }: { exams: ExamOption[]
   }, [classes, searchParams])
   const [classId, setClassId] = useState<string>(initialClassId)
   const [allowLate, setAllowLate] = useState<boolean>(false)
+  const [isSubmitting, setIsSubmitting] = useState(false)
 
   const handleSubmit = async (formData: FormData) => {
-    if (!examId) {
-      toast.error("Please select an exam")
+    if (mode === "exam" && !examId) {
+      toast.error(t("homework.form.selectExamRequired"))
+      return
+    }
+    if (mode === "quick" && !formData.get("title")) {
+      toast.error(t("homework.form.titleRequired"))
       return
     }
     if (!classId) {
-      toast.error("Please select a class")
+      toast.error(t("homework.form.selectClassRequired"))
       return
     }
-    formData.set("sourceExamId", examId)
+
+    if (mode === "exam") {
+      formData.set("sourceExamId", examId)
+    } else {
+      formData.delete("sourceExamId")
+    }
     formData.set("classId", classId)
     formData.set("allowLate", allowLate ? "true" : "false")
     formData.set("publish", "true")
 
+    setIsSubmitting(true)
     const result = await createHomeworkAssignmentAction(null, formData)
+    setIsSubmitting(false)
     if (result.success) {
       toast.success(result.message)
       router.push("/teacher/homework/assignments")
     } else {
-      toast.error(result.message || "Failed to create")
+      toast.error(result.message || t("homework.form.createFailed"))
     }
   }
 
   return (
-    <Card>
+    <Card className="relative">
+      {isSubmitting && (
+        <div className="absolute inset-0 z-10 flex items-center justify-center rounded-lg bg-background/60 backdrop-blur-sm">
+          <div className="flex items-center gap-2 text-sm font-medium">
+            <div className="h-4 w-4 animate-spin rounded-full border-2 border-primary border-t-transparent" />
+            {t("homework.form.creating")}
+          </div>
+        </div>
+      )}
       <CardHeader>
-        <CardTitle>Create Assignment</CardTitle>
+        <CardTitle>{t("homework.form.createTitle")}</CardTitle>
       </CardHeader>
       <CardContent>
         <form action={handleSubmit} className="space-y-6">
+          {/* 模式切换 */}
+          <div className="grid grid-cols-2 gap-2">
+            <button
+              type="button"
+              onClick={() => setMode("quick")}
+              className={cn(
+                "flex items-center gap-2 rounded-md border p-3 text-left transition-colors",
+                mode === "quick"
+                  ? "border-primary bg-primary/5 text-primary"
+                  : "border-border hover:bg-muted/50"
+              )}
+            >
+              <FileText className="h-4 w-4 shrink-0" aria-hidden="true" />
+              <div>
+                <div className="text-sm font-medium">{t("homework.form.quickMode")}</div>
+                <div className="text-xs text-muted-foreground">{t("homework.form.quickModeDescription")}</div>
+              </div>
+            </button>
+            <button
+              type="button"
+              onClick={() => setMode("exam")}
+              disabled={exams.length === 0}
+              className={cn(
+                "flex items-center gap-2 rounded-md border p-3 text-left transition-colors disabled:cursor-not-allowed disabled:opacity-50",
+                mode === "exam"
+                  ? "border-primary bg-primary/5 text-primary"
+                  : "border-border hover:bg-muted/50"
+              )}
+            >
+              <FileQuestion className="h-4 w-4 shrink-0" aria-hidden="true" />
+              <div>
+                <div className="text-sm font-medium">{t("homework.form.examMode")}</div>
+                <div className="text-xs text-muted-foreground">{t("homework.form.examModeDescription")}</div>
+              </div>
+            </button>
+          </div>
+
           <div className="grid grid-cols-1 gap-4 md:grid-cols-2">
             <div className="grid gap-2 md:col-span-2">
-              <Label>Class</Label>
+              <Label>{t("homework.form.class")}</Label>
               <Select value={classId} onValueChange={setClassId}>
                 <SelectTrigger>
-                  <SelectValue placeholder="Select a class" />
+                  <SelectValue placeholder={t("homework.form.selectClass")} />
                 </SelectTrigger>
                 <SelectContent>
                   {classes.map((c) => (
@@ -89,40 +152,54 @@ export function HomeworkAssignmentForm({ exams, classes }: { exams: ExamOption[]
               <input type="hidden" name="classId" value={classId} />
             </div>
 
+            {mode === "exam" && (
+              <div className="grid gap-2 md:col-span-2">
+                <Label>{t("homework.form.sourceExam")}</Label>
+                <Select value={examId} onValueChange={setExamId}>
+                  <SelectTrigger>
+                    <SelectValue placeholder={t("homework.form.selectExam")} />
+                  </SelectTrigger>
+                  <SelectContent>
+                    {exams.map((e) => (
+                      <SelectItem key={e.id} value={e.id}>
+                        {e.title}
+                      </SelectItem>
+                    ))}
+                  </SelectContent>
+                </Select>
+                <input type="hidden" name="sourceExamId" value={examId} />
+              </div>
+            )}
+
             <div className="grid gap-2 md:col-span-2">
-              <Label>Source Exam</Label>
-              <Select value={examId} onValueChange={setExamId}>
-                <SelectTrigger>
-                  <SelectValue placeholder="Select an exam" />
-                </SelectTrigger>
-                <SelectContent>
-                  {exams.map((e) => (
-                    <SelectItem key={e.id} value={e.id}>
-                      {e.title}
-                    </SelectItem>
-                  ))}
-                </SelectContent>
-              </Select>
-              <input type="hidden" name="sourceExamId" value={examId} />
+              <Label htmlFor="title">
+                {t("homework.form.assignmentTitle")} {mode === "quick" && <span className="text-destructive">*</span>}
+              </Label>
+              <Input
+                id="title"
+                name="title"
+                placeholder={mode === "exam" ? t("homework.form.titlePlaceholderExam") : t("homework.form.titlePlaceholderQuick")}
+                required={mode === "quick"}
+              />
             </div>
 
             <div className="grid gap-2 md:col-span-2">
-              <Label htmlFor="title">Assignment Title (optional)</Label>
-              <Input id="title" name="title" placeholder="Defaults to exam title" />
-            </div>
-
-            <div className="grid gap-2 md:col-span-2">
-              <Label htmlFor="description">Description (optional)</Label>
-              <Textarea id="description" name="description" className="min-h-[80px]" />
+              <Label htmlFor="description">{t("homework.form.description")}</Label>
+              <Textarea
+                id="description"
+                name="description"
+                className="min-h-[80px]"
+                placeholder={mode === "quick" ? t("homework.form.descriptionPlaceholderQuick") : undefined}
+              />
             </div>
 
             <div className="grid gap-2">
-              <Label htmlFor="availableAt">Available At (optional)</Label>
+              <Label htmlFor="availableAt">{t("homework.form.availableAt")}</Label>
               <Input id="availableAt" name="availableAt" type="datetime-local" />
             </div>
 
             <div className="grid gap-2">
-              <Label htmlFor="dueAt">Due At (optional)</Label>
+              <Label htmlFor="dueAt">{t("homework.form.dueAt")}</Label>
               <Input id="dueAt" name="dueAt" type="datetime-local" />
             </div>
 
@@ -133,29 +210,19 @@ export function HomeworkAssignmentForm({ exams, classes }: { exams: ExamOption[]
                 checked={allowLate}
                 onChange={(e) => setAllowLate(e.target.checked)}
               />
-              <Label htmlFor="allowLate">Allow late submissions</Label>
+              <Label htmlFor="allowLate">{t("homework.form.allowLate")}</Label>
               <input type="hidden" name="allowLate" value={allowLate ? "true" : "false"} />
             </div>
 
             <div className="grid gap-2">
-              <Label htmlFor="lateDueAt">Late Due At (optional)</Label>
+              <Label htmlFor="lateDueAt">{t("homework.form.lateDueAt")}</Label>
               <Input id="lateDueAt" name="lateDueAt" type="datetime-local" />
             </div>
 
             <div className="grid gap-2">
-              <Label htmlFor="maxAttempts">Max Attempts</Label>
+              <Label htmlFor="maxAttempts">{t("homework.form.maxAttempts")}</Label>
               <Input id="maxAttempts" name="maxAttempts" type="number" min={1} max={20} defaultValue={1} />
             </div>
-
-            <div className="grid gap-2 md:col-span-2">
-              <Label htmlFor="targetStudentIdsText">Target student IDs (optional)</Label>
-              <Textarea
-                id="targetStudentIdsText"
-                name="targetStudentIdsText"
-                placeholder="Optional. If provided, targets will be limited to students in the selected class."
-                className="min-h-[90px]"
-              />
-            </div>
           </div>
 
           <CardFooter className="justify-end">