Initialize Nix Flake

Set up a Nix flake with bun and typescript for development.

Steps

1. Check for existing flake.nix - ask before overwriting

2. Get project name from directory name or package.json if exists

3. Create flake.nix:

   {
     description = "<project-name>";
   
     inputs = {
       nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
     };
   
     outputs = {nixpkgs, ...}: let
       forAllSystems = function:
         nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed
         (system: function nixpkgs.legacyPackages.${system});
     in {
       formatter = forAllSystems (pkgs: pkgs.alejandra);
       devShells = forAllSystems (pkgs: {
         default = pkgs.mkShell {
           packages = with pkgs; [
             bun
             typescript
             lefthook
           ];
         };
       });
     };
   }

4. Create .envrc (if not exists):

   use flake

5. Add to .gitignore (if not present):

   .direnv/
   result

6. Run direnv allow if direnv is available

7. Summary: Created files, remind to run nix develop or let direnv activate

Notes

• This creates a minimal devShell; add more packages as needed
• For projects needing nix packaging (bun2nix), that's a separate enhancement
• lefthook included by default for git hooks support