fix(agent): 错误诊断 - 读取最近上游响应状态

backend/internal/repository/analytics.go

@@ -229,6 +229,18 @@ func (r *Repository) APICallLogUsageForTask(userID, taskID string) (model.ApiCal
 	return log, true, nil
 }
 
+// LatestAPICallStatusForTask 返回任务最近一次上游调用的 HTTP 状态码；
+// 任务没收到任何上游响应（例如网络错误）时返回 0。
+func (r *Repository) LatestAPICallStatusForTask(taskID string) (int, error) {
+	if strings.TrimSpace(taskID) == "" {
+		return 0, nil
+	}
+	var log model.ApiCallLog
+	err := r.db.Select("status_code").Where("task_id = ? AND request_kind <> ?", taskID, "poll").
+		Order("created_at DESC").Limit(1).Find(&log).Error
+	return log.StatusCode, err
+}
+
 func (r *Repository) HasAPICallLogForTask(taskID string) (bool, error) {
 	if strings.TrimSpace(taskID) == "" {
 		return false, nil