feature request: remove `nui.nvim`

[barrettruth]

Hello Yanuo, I think this plugin is awesome and paves the way towards a modern NeoVim with VsCode feature parity.

I'd like to remove the plugin dependency on nui.nvim for three reasons:

1. This is more of a philosophical question in which I and others think "a neovim diff plugin should not have a UI framework dependency."
2. I also think the UI is, for the use of most people, not going to be leveraged to the point where nui.nvim is warranted (opinion).
3. I am also of the opinion that in the long run these UI frameworks will all be removed and centralized eventually - with the pace of neovim development, that may be in the next couple of months.
4. NeoVim is quirky - and this is the type of things that people (including myself) actually care about. Oftentimes (you can see it on reddit frequently) people are actually completely dissuaded from even using a plugin because of seemingly superfluous dependencies (plenary.nvim in 2026, ui frameworks, etc.)

I also commented on the request for a unified diff; are you open to contributions? I'd love to work on either of these features.

[barrettruth]

UPD: after exploring this plugin more, I think a config option or command-mode flag that simply DISABLES the explorer tree, coupled with a few nice mappings to replace the tree (such as some nice mappings to browse between files, if they don't already exist) would be sufficient.

Then, all that's needed would be to document this plugin as optional once in the readme and that's it!