feat: add devenv

modules/features/dev-tools.nix

@@ -1,8 +1,9 @@
 {
   flake.modules.homeManager.dev-tools =
-    { config, ... }:
+    { config, pkgs, ... }:
     {
       home.sessionVariables.CARGO_HOME = "${config.xdg.dataHome}/cargo";
+      home.packages = [ pkgs.devenv ];
 
       programs.direnv = {
         enable = true;