feat(后台 AI 报告): 报告列表带上学生是哪个班的

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/contract/src/admin.ts

@@ -190,6 +190,8 @@ export const updateExerciseRequestSchema = createExerciseRequestSchema.omit({
 export const adminAiReportListItemSchema = z.object({
   id: z.number().int(),
   username: z.string(),
+  /** 列表里名字旁边写是哪个班的 */
+  className: z.string().nullable(),
   createTime: z.string(),
   analysisExcerpt: z.string(),
   isPinned: z.boolean(),