Add Just Command Runner and Treefmt-nix; Fix Minor Bugs

[use-the-fork]

This pull request introduces the Just command runner and Treefmt-nix, and includes fixes for several minor bugs.

Key Additions:

1. Just Command Runner:

   • Implements the Just command runner for seamless script integration.
   • Integrates with pre-commit, treefmt-nix, devenv up, and version.
   • Includes sample Just scripts for initial use and further development.
   • Adds the default justfile, which imports just.flake into REQUIRED_FILES for proper setup.
   • Updates documentation to include new options and settings for the Just command runner.

2. Treefmt-nix:

   • Integrates Treefmt-nix into devenv.
   • Updates documentation to detail the Treefmt-nix configuration and usage.

3. Development Environment Updates (devenv.nix):

   • Enhances the build process for documentation to avoid npx dependencies by using Nix's pkgs.tailwindcss package.

Issues Addressed:

• Closes Adding commands to devenv #117
• Closes Print version information when entering shell #739
• Closes Integrate treefmt-nix #533

[use-the-fork]

Let me know if there is anything you all need me to do with this module. I added docs and tests today.

[use-the-fork]

@domenkozar I'm not sure if I did everything you need to merge this. Just so you know, I use AI to help write the PR and commit messages. I do all the coding myself but AI does a better job at making my documentation clear :)

[I-Want-ToBelieve]

@domenkozar

[use-the-fork]

@sandydoo @domenkozar I'm very pleased with the current integration after today's refactor, which streamlined the just runner. I have other integrations ready in a separate branch for a PR, but I prefer to get this merged first. I understand it's a significant change and am eager to assist in any way needed.

So let me know thanks!

[domenkozar]

Hey, can you split this PR into separate ones for each issue? That way it makes it easier to review.