me/my/I function #3

With the current GitHub MCP server a request like "summarize all of the latest commits on my X repo" (where X is private) will fail because the server will often not fill out the correct username. We should provide a function that returns the authed user's information for any reference to "me", "my", "I"... The model should call this function before further function calls that require authed access (which it should do if the function description is broad enough).