[Feature Request / Permission] Implement catppuccin palette in sdnext modernui

Hello,

We just released the new [modern ui](https://github.com/BinaryQuantumSoul/sdnext-modernui).

I was wondering if you could port the cappuccin themes to this ui too ? If you don't have time to do so, do you grant me permission to implement it myself ? Obviously I don't want to force anything, I just thought it would be a nice collab

Start by reviewing the modern UI project linked in the issue and comparing its theme structure with this repository's existing palettes. The work is done when the Catppuccin themes are ported to the sdnext modern UI and the available themes render consistently there.

Written by the indexing model from the issue text.