Improve pre-tool agent hooks to provide more MCP-specific information

In the [PreToolUse hook](https://code.visualstudio.com/docs/agents/reference/hooks-reference#_pretooluse), we are provided with the tool name, but in the case where it is a tool in an MCP server, we are not told the full server name or any other information about the server (such as its URL or command). This information would be helpful for me to capture in hooks. I believe a truncated form of the server's name in the configuration is included as part of the tool name, but this is not enough information for me.

A separate `PreMCPExecution` hook (or something like that) would be nice too, if that is a cleaner design. That is what Cursor does.