debug: 添加更早的调试日志

backend/app/service/ApprovalService.php

@@ -264,6 +264,8 @@ class ApprovalService
             }
 
             if ($currentNode) {
+                error_log("🔧 准备更新消息卡片: currentNode存在, notificationService=" . ($this->notificationService ? '存在' : 'null'));
+
                 // 更新操作人自己的消息卡片
                 $this->notificationService->setAppByUser($approverId);
                 $this->notificationService->updateActorMessageCard(