Apply best practices

[aster-void]

changes:

• style: split the code into multiple files
• style: remove unused code
• add: .helix/languages.toml for code formatting in helix editor
• format: set strict option to nixfmt
  • updated flake, because this is a new feature (~2 weeks old) in treefmt-nix
• doc: add inputs.prisma-utils.inputs.nixpkgs.follows = "nixpkgs"; for deduplication
• (todo) test: use package manager to invoke prisma commands rather than manually calling them