cleanup, modularise

modules/home/programs/terminal/ghostty.nix

@@ -0,0 +1,21 @@
+{
+  config,
+  lib,
+  ...
+}:
+with lib; let
+  cfg = config.terminal.ghostty;
+in {
+  options = {
+    terminal.ghostty.enable = mkEnableOption "enable ghostty terminal";
+  };
+  config = mkIf cfg.enable {
+    programs.ghostty = {
+      enable = true;
+      settings = {
+        gtk-single-instance = true;
+        window-decoration = "client";
+      };
+    };
+  };
+}