fix: update context logging type hints to allow any JSON-serializable data

[cubaseuser123]

The issue here comes down to a frustrating type mismatch: the MCP spec clearly states that log message data can be any JSON-serializable type, but the convenience wrappers for ctx.info(), ctx.warning(), etc., were strictly enforcing message: str. So whenever a dev tried to log a simple Python dictionary or list, the type checker would throw a fit.

I traced it down and the good news is the underlying send_log_message method already handles Any properly without trying to blindly stringify things. The bug was entirely superficial.

So I went in and updated the surface-level type hints to bring the API back into alignment with the spec.

Specifically, this updates message: str to message: Any across:

• ctx.log()
• ctx.info()
• ctx.debug()
• ctx.warning()
• ctx.error()

Validation:
I ran the full pytest suite against mcpserver/test_server.py and client/test_logging_callback.py — all 90 tests ran cleanly with no regressions to the existing logging behavior.

(Side note: I didn't have to touch any serialization logic, since the transport layer already handles the Any payload exactly as it should).

Let me know if there's anything else you'd like me to tweak before we merge this in! Fixes #397.

[maxisbey]

Thanks for the PR, but closing in favour of #2366