add niux to Command-Line Tools

[sayavc]

It automates package management by interacting with configuration files via markers, supporting both Flakes and legacy setups.

[cyntheticfox]

So, this project doesn't seem "awesome" to me in a couple of ways:

• The intent of the tool the project provides is literally counter to Nix. Running a command to modify the system's configuration is the definition of "imperative".
• Rust code with a lot of unwraps, shell execs, and calls to sudo. Beyond code stability, I'm not so sure this code is secure (it almost feels lightly obfuscated), and I don't feel it's worth the time to thoroughly test it
• Commit documentation is sparse to nonexistant and absolutely massive
• The release tagging is all over the place. At the time of writing, the 3 releases are v1.0.0, 1.2.3-legacy, and v26.04.
• Literally all of this could be effectively done using a shell script, and I still wouldn't recommend it.