fix(agui_protocol): import run event classes directly

the runstartedevent and runfinishedevent classes are now imported directly from ag_ui.core to ensure proper event handling in the sse stream.

these events are essential for signaling the start and completion of runs within the agui protocol, improving reliability and maintainability of the streaming mechanism.

修复了 agui 协议中运行事件类的导入问题，确保 SSE 流能够正确处理运行开始和结束事件。此举增强了流机制的可靠性和可维护性。

Change-Id: Ied78843c9533c640a4706b379c8bd9109acc3b0b
Signed-off-by: OhYee <[email protected]>

Author: OhYee

agentrun/model/model.py

@@ -131,6 +131,7 @@ class ProxyConfigTokenRateLimiter(BaseModel):
 
 class ProxyConfigAIGuardrailConfig(BaseModel):
     """AI 防护配置"""
+
     check_request: Optional[bool] = None
     check_response: Optional[bool] = None
 

agentrun/server/agui_protocol.py

@@ -347,6 +347,8 @@ async def _format_stream(
         Yields:
             SSE 格式的字符串
         """
+        from ag_ui.core import RunFinishedEvent, RunStartedEvent
+
         state = StreamStateMachine()
 
         # 发送 RUN_STARTED