feat: terminal layout and functionality

[gacallea]

Improve native nvim terminal:

• [x] resemble webchuck ui layout
• [x] only have the splits open but not the corresponding buffers

edit: consider using nui.nvim splits instead

[gacallea]

layout: https://github.com/gacallea/chuck-nvim/commit/ae082f820097d698f9e2a7567559968931f9dd41

[gacallea]

nui does what I need. will implement proper code soon.