feat: 优化考试记录接口，支持从任务反推科目名称；更新测试用例以验证新逻辑

api/controllers/quizController.ts

@@ -163,12 +163,24 @@ export class QuizController {
       const result = await QuizModel.submitQuiz({ userId, answers: processedAnswers });
 
       if (subjectId || taskId) {
+        let finalSubjectId: string | null = subjectId || null;
+        const finalTaskId: string | null = taskId || null;
+
+        // 任务考试场景下，如果前端未传subjectId，则从任务中反查
+        if (!finalSubjectId && finalTaskId) {
+          const { ExamTaskModel } = await import('../models/examTask');
+          const task = await ExamTaskModel.findById(finalTaskId);
+          if (task?.subjectId) {
+            finalSubjectId = task.subjectId;
+          }
+        }
+
         const sql = `
           UPDATE quiz_records 
           SET subject_id = ?, task_id = ? 
           WHERE id = ?
         `;
-        await import('../database').then(({ run }) => run(sql, [subjectId || null, taskId || null, result.record.id]));
+        await import('../database').then(({ run }) => run(sql, [finalSubjectId, finalTaskId, result.record.id]));
       }
 
       res.json({