本次新增 MCP 工具执行的手动终止能力：在监控中可对单次正在运行的工具调用发送取消信号，而不打断整条对话或迭代任务；支持在终止时填写说明，服务端将工具已产生的输出（若有）与说明合并后交给大模型，并通过固定标题块标明「用户终止说明」，与命令行/工具原始输出区分。配套包含取消接口（可选 note）、前端终止弹窗及相关文案与 API 描述。
This release adds manual cancellation for in-flight MCP tool runs from the monitor: you can stop a single tool call without stopping the whole chat or agent loop, optionally attach an operator note; the server merges any partial tool output with that note for the model and prefixes it with a clear user interrupt banner so it is not mistaken for raw tool output. The feature includes the cancel API (optional note body), the termination modal in the UI, and updated copy/OpenAPI documentation.
