ui: refactor text with raylib

[sunnyhaibin]

Qt	Raylib

[adeebshihadeh]

So the really important thing to make sure with text is that we can easily make the scrolling good (iPhone-quality) on raylib. Maybe @deanlee has already investigated this?

If that's not easy with raylib, we'll have to look into something else. This UI rewrite is all about fixing the lag: from building to the actual input in the UI.

[deanlee]

@sunnyhaibin Great work! That said, the scrolling implementation seems a bit more complex than necessary. I wanted to share a draft of ui_text I previously worked on using Raylib: link to text.cc, This draft implements a scrollable text area using raylib’s ScissorMode. Feel free to take a look and see if there’s anything you find useful or applicable for reference.

Additionally, to fully migrate all UI components, we might need to consider integrating rayui (a single-file, header-only library). This can simplify a lot of tasks, including handling scrolling-related components. I haven’t tried rayui yet, but you can give it a try if you’re interested.