关于文章 `ai/agent/mcp.md` 的 MCP 2026-07-28 版本跟进

The article in docs/ai/agent/mcp.md states, “This article is based on the current stable revision 2025-11-25.” However, the most recent official stable version is 2026-07-28, as described in the official blog: The 2026-07-28 Specification. Because this update is a disruptive change, the official transition of the protocol is toward stateless, independent requests, and many details have changed, such as the new version removes the handshake and transport session, and Mcp-Session-Id is removed. Some parts of the original text are no longer applicable. Therefore, if readers understand and implement the protocol according to this article, they may not be able to use the new SDK. It is recommended to change the version description of the documentation and gradually replace outdated specific statements.