🐛 fix(exam): 修复教室数据查询参数格式错误

- 修改查询参数格式，使用JSON.stringify包装filters对象
- 更正classroom_no参数名为classroomNo以匹配后端接口要求

src/client/mobile/components/Exam/ExamCard.tsx

@@ -36,7 +36,7 @@ export default function ExamCard() {
     queryFn: async () => {
       if (!classroom) return null;
       const response = await classroomDataClient.$get({
-        query: { classroom_no: classroom }
+        query: { filters: JSON.stringify({ classroomNo: classroom }) }
       });
       if (response.status !== 200) {
         message.error('获取教室数据失败');