Introduce neo ci Subcommands for CI/CD and External Integrations

[NickSeagull]

Currently, the build command in the NeoHaskell CLI follows this process:

1. Generates a Haskell Cabal file in a temporary location.
2. Creates a Nix file.
3. Uses the Nix file as an expression for the Nix build command.

While this approach works, it lacks flexibility for CI/CD and integration with external projects. Instead, we should introduce a neo ci command with subcommands that allow finer control over the build process.

Proposed Changes:

1. Introduce new ci subcommands:
   • neo ci generate-cabal: Generates a Cabal file but does not trigger a build.
   • neo ci generate-nix: Generates a Nix file but does not trigger a build.
   • Future extensions (e.g., neo ci build, neo ci test) could be added later.
2. Modify the build command so it does not implicitly generate Cabal/Nix files but instead relies on existing ones or explicitly calls neo ci generate-* when needed.
3. Ensure NeoHaskell itself can use this system in its own CI/CD pipelines.

Benefits:

• Enables proper CI/CD automation with explicit file generation.
• Makes NeoHaskell CLI easier to integrate with external projects.
• Allows .cabal and .nix files to be safely ignored in repositories.
• Reduces unnecessary file regeneration, improving efficiency.