Add group to tools

Hello, I would like to add a group request endpoint, and mark which group it belongs to when registering tools. When using the SSE endpoint, describe the group in the path or parameters. When the client pulls the tool list, it returns the tools of the specified group (if no group is specified, all are returned).

I expect to solve the problem:

1 When a server has many tools, I don't want to use multiple endpoints to group these tools, which is simpler when used in a framework like Spring.
2 Configure different groups to express different agents by obtaining different tool lists.

Note: Alternatively, add a group by interface to handle the group names passed by the SSE endpoint. This interface receives the group name and tools list context, and returns the tools list corresponding to the group name.

首先追蹤現有的 SSE 端點、工具註冊流程和工具清單回應。在決定採用端點變更還是分組介面之前，先檢查目前如何處理請求參數和已註冊工具。完成標準是：伺服器可以依群組註冊工具，透過 SSE 請求一個群組，並在未指定群組時接收該群組或所有工具。