[Bug] 百度AI搜索失效 #3676
Description
What happened / 发生了什么
在配置文件中把网络搜索提供商设置为百度AI搜索，并长时间开启AstrBot后（通常是几个小时）AI搜索回失效
重启AstrBot可短暂修复问题，但是过了几小时仍然会出现失效
Reproduce / 如何复现？
- 在配置文件中把网页搜索提供商设置为baidu_ai_search
- 使用Bot进行一次AI搜索的操作，大概率正常回复
- 等待数小时
- 再次进行AI搜索操作，问题复现
AstrBot version, deployment method (e.g., Windows Docker Desktop deployment), provider used, and messaging platform used. / AstrBot 版本、部署方式（如 Windows Docker Desktop 部署）、使用的提供商、使用的消息平台适配器
4.5.8 手动部署 macOS 15.7 Python3.13.9
模型提供商 Google gemini (gemini-2.5-flash) 消息平台 aiocqhttp、telegram bot
4.5.8 Windows Launcher Python3.13.9 也可复现
OS
macOS
Logs / 报错日志
```
[17:48:20] [Core] [INFO] [runners.tool_loop_agent_runner:247]: 使用工具：AIsearch，参数：{'query': '最近有什么新番值得看 推荐'}
[17:48:20] [Core] [WARN] [runners.tool_loop_agent_runner:388]: Traceback (most recent call last):
File "/Users/linghuservers/AstrBot/astrbot/core/agent/runners/tool_loop_agent_runner.py", line 304, in _handle_function_tools
async for resp in executor: # type: ignore
File "/Users/linghuservers/AstrBot/astrbot/core/astr_agent_tool_exec.py", line 42, in execute
async for r in cls._execute_mcp(tool, run_context, **tool_args):
File "/Users/linghuservers/AstrBot/astrbot/core/astr_agent_tool_exec.py", line 180, in _execute_mcp
res = await tool.call(run_context, **tool_args)
File "/Users/linghuservers/AstrBot/astrbot/core/agent/mcp_client.py", line 252, in call
res = await session.call_tool(
File "/Users/linghuservers/AstrBot/.venv/lib/python3.10/site-packages/mcp/client/session.py", line 293, in call_tool
result = await self.send_request(
File "/Users/linghuservers/AstrBot/.venv/lib/python3.10/site-packages/mcp/shared/session.py", line 261, in send_request
await self._write_stream.send(SessionMessage(message=JSONRPCMessage(jsonrpc_request), metadata=metadata))
File "/Users/linghuservers/AstrBot/.venv/lib/python3.10/site-packages/anyio/streams/memory.py", line 243, in send
self.send_nowait(item)
File "/Users/linghuservers/AstrBot/.venv/lib/python3.10/site-packages/anyio/streams/memory.py", line 212, in send_nowait
raise ClosedResourceError
anyio.ClosedResourceError
### Are you willing to submit a PR? / 你愿意提交 PR 吗？
- [ ] Yes!
### Code of Conduct
- [x] I have read and agree to abide by the project's [Code of Conduct](https://docs.github.com/zh/site-policy/github-terms/github-community-code-of-conduct)。