fix: scope transactional locks to primary records

backend/apps/knowledge/distillation.py

@@ -146,7 +146,7 @@ def start_ticket_knowledge_distillation(
     """从可信解决结果启动幂等蒸馏运行，并冻结工单输入快照。"""
 
     ticket = (
-        Ticket.objects.select_for_update()
+        Ticket.objects.select_for_update(of=("self",))
         .select_related("category", "resolution")
         .get(id=ticket.id)
     )
@@ -255,7 +255,7 @@ def process_knowledge_distillation_result(
     if run.definition.code != KNOWLEDGE_DISTILLATION_AGENT_CODE or run.status != "succeeded":
         return None
     distillation = (
-        TicketKnowledgeDistillation.objects.select_for_update()
+        TicketKnowledgeDistillation.objects.select_for_update(of=("self",))
         .select_related("ticket__category", "ticket__resolution", "run__created_by")
         .get(run=run)
     )