Persist active run event history

src/agent_runtime.py

@@ -1270,9 +1270,15 @@ class LocalCodingAgent:
                     self.last_run_result = result
                     return result
 
-        final_output = (
-            last_content
-            or 'Stopped: max turns reached before the model produced a final answer.'
+        final_output = self._build_max_turns_output(
+            max_turns=self.runtime_config.max_turns,
+            last_content=last_content,
+            tool_calls=tool_calls,
+        )
+        session.append_assistant(
+            final_output,
+            message_id=f'assistant_{len(session.messages)}',
+            stop_reason='max_turns',
         )
         _append_final_text_stream_events(stream_events, final_output)
         result = AgentRunResult(
@@ -1299,6 +1305,23 @@ class LocalCodingAgent:
         self.last_run_result = result
         return result
 
+    @staticmethod
+    def _build_max_turns_output(
+        *,
+        max_turns: int,
+        last_content: str,
+        tool_calls: int,
+    ) -> str:
+        lines = [
+            f'已达到本轮最大步骤上限（{max_turns} 轮），为了避免继续空转，当前任务已暂停。',
+        ]
+        if tool_calls:
+            lines.append('最后一轮已经执行完工具，但还没有来得及整理成最终回复。')
+        if last_content.strip():
+            lines.append(f'最后一次阶段说明：{last_content.strip()}')
+        lines.append('你可以继续补充指令，我会基于当前会话结果接着处理。')
+        return '\n\n'.join(lines)
+
     def _query_model(
         self,
         session: AgentSessionState,