feat(shell): add enable option

home/modules/shell/prompt.nix

@@ -1,3 +1,11 @@
 {
-  programs.starship.enable = true;
+  config,
+  lib,
+  ...
+}:
+
+{
+  config = lib.mkIf config.shell.enable {
+    programs.starship.enable = true;
+  };
 }