flakes: Migrate the config and miku to flakes

modules/programs/gnome/default.nix

@@ -1,7 +1,13 @@
 { pkgs, config, lib, ... }:
 
-{
-  config = {
+let
+  cfg = config.ptw.services.gnome;
+in {
+  options.ptw.services.gnome = {
+    enable = lib.mkEnableOption "Configure GNOME using HomeManager";
+  };
+  
+  config = lib.mkIf cfg.enable {
     environment = {
       systemPackages = with pkgs; [
         arc-theme
@@ -68,7 +74,7 @@
       gtkUsePortal = true;
     };
 
-    home-manager.users."${config.system.singleUser}" = {
+    home-manager.users."${config.ptw.system.singleUser}" = {
       xdg.configFile = {
         # Make QT apps use a dark theme
         "Kvantum/kvantum.kvconfig".text = ''