修复: MissingGreenlet_product访问try/catch + spawn_subtask不再覆盖overall_status

backend/app/services/product_service.py

@@ -15,11 +15,19 @@ from app.schemas.task import TaskSummaryResponse, TaskResponse, TaskRecordRespon
 
 def _task_to_response(task: Task) -> TaskResponse:
     """将 Task ORM 对象递归转为 TaskResponse（含子任务树）"""
+    product_sn = ""
+    product_material = ""
+    try:
+        if task.product:
+            product_sn = task.product.serial_number or ""
+            product_material = (task.product.material_name or task.product.material_id or "")
+    except Exception:
+        pass
     return TaskResponse(
         id=task.id,
         product_id=task.product_id,
-        product_sn=task.product.serial_number if task.product else "",
-        product_material=task.product.material_name or task.product.material_id or "" if task.product else "",
+        product_sn=product_sn,
+        product_material=product_material,
         parent_task_id=task.parent_task_id,
         task_name=task.task_name,
         assignee_id=task.assignee_id,