[Idea] Core Text APIs for MewUI

[lextm]

I built Core Text APIs for Uno Platform based on many of your attempts to implement IME integration in MewUI.

I think if there is a "Core Text APIs for MewUI", then any third party input control for MewUI can benefit from it too, and those authors don't need to integrate with IME again in their own controls.

This can be a separate repo, but I believe it should be part of this main repo for other control authors to consume.