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/i18n/request.ts

@@ -35,6 +35,8 @@ export default getRequestConfig(async () => {
     lessonPreparation,
     grades,
     diagnostic,
+    attendance,
+    elective,
   ] = await Promise.all([
     import(`@/shared/i18n/messages/${locale}/common.json`),
     import(`@/shared/i18n/messages/${locale}/auth.json`),
@@ -51,6 +53,8 @@ export default getRequestConfig(async () => {
     import(`@/shared/i18n/messages/${locale}/lesson-preparation.json`),
     import(`@/shared/i18n/messages/${locale}/grades.json`),
     import(`@/shared/i18n/messages/${locale}/diagnostic.json`),
+    import(`@/shared/i18n/messages/${locale}/attendance.json`),
+    import(`@/shared/i18n/messages/${locale}/elective.json`),
   ]);
 
   return {
@@ -71,6 +75,8 @@ export default getRequestConfig(async () => {
       lessonPreparation: lessonPreparation.default,
       grades: grades.default,
       diagnostic: diagnostic.default,
+      attendance: attendance.default,
+      elective: elective.default,
     },
   };
 });