fix: 协助卡停轮与提交防 409，隐藏配置向导会话，并限制岗位会商产物重复写入

澄清中间件改为 ToolMessage + after_model 停轮，前端提交前取消残留 run；系统/向导 thread_type 从对话列表排除；岗位总结席位加 write_file 上限。

Co-authored-by: Cursor <cursoragent@cursor.com>

offline-backend-20260512/backend/packages/harness/deerflow/agents/lead_agent/agent.py

@@ -368,6 +368,13 @@ def _build_middlewares(
 
         middlewares.append(SkillReviewMiddleware())
 
+    # PositionArtifactCapMiddleware — position-roundtable seats (and summary)
+    # may only emit N outputs write_file calls per user turn. Action-plan skips
+    # the context flag so it can still write report + JSON.
+    from deerflow.agents.middlewares.position_artifact_cap_middleware import PositionArtifactCapMiddleware
+
+    middlewares.append(PositionArtifactCapMiddleware())
+
     # LoopDetectionMiddleware — detect and break repetitive tool call loops
     middlewares.append(LoopDetectionMiddleware())