fix: enable nh in base cli

modules/applications/nh.nix

@@ -0,0 +1,21 @@
+{
+  username,
+  lib,
+  config,
+  ...
+}:
+let
+  cfg = config.my.applications.nh;
+in
+{
+  options.my.applications.nh = {
+    enable = lib.mkEnableOption "nh Nix CLI helper";
+  };
+
+  config = lib.mkIf cfg.enable {
+    programs.nh = {
+      enable = true;
+      flake = "/home/${username}/dotfiles";
+    };
+  };
+}