Looks great, I'm definitely going to have a look at it.
Off-topic: it'd be nice to have a configuration spec to define the look (and maybe even the behaviour) of the different CLI & TUI libraries out there. For things like colours/borders/corners/shadows/scroll- & progressbars etc.
Right now every library does its own thing, which can be quite jarring when using different apps.
I guess, to a degree, this is what lipgloss is trying to be/solve: https://github.com/marcoroth/lipgloss-ruby