feat: improve agent workflow observability

backend-fastapi/ai_platform/api/agent_api.py

@@ -422,8 +422,23 @@ async def publish_agent(agent_id: str, db: AsyncSession = Depends(get_db)):
     
     # 验证必要配置
     if agent.mode == "autonomous":
-        if not agent.model_id:
-            raise HTTPException(status_code=400, detail="请先配置模型")
+        if agent.model_id:
+            model_result = await db.execute(
+                select(LLMModel).where(
+                    LLMModel.id == agent.model_id,
+                    LLMModel.is_deleted == False,
+                )
+            )
+            model = model_result.scalar_one_or_none()
+            if not model:
+                raise HTTPException(status_code=400, detail="模型不存在")
+            if not model.is_active:
+                raise HTTPException(status_code=400, detail="模型已禁用")
+        elif not await _resolve_default_chat_model_id(db):
+            raise HTTPException(
+                status_code=400,
+                detail="请先在模型配置中启用一个 chat 模型，或为智能体指定模型",
+            )
     elif agent.mode == "dialog_flow":
         if not agent.workflow_id:
             raise HTTPException(status_code=400, detail="对话流模式需要配置工作流")