feat(nix): add desktop module and refactor machine options

nix/manifest.nix

@@ -1,15 +1,3 @@
-let
-  testCfg = {
-    machine = {
-      bluetooth.enable = true;
-      usb.automount = true;
-      virtualisation.podman = {
-        enable = true;
-        distrobox.enable = true;
-      };
-    };
-  };
-in
 {
   flake.manifest = {
     users.rafiq = {
@@ -34,14 +22,13 @@ in
             }
           ];
         };
-        extraCfg = testCfg;
+        extraCfg.desktop.enable = true;
       };
       apollo = {
         machine = {
           platform = "intel";
           root.drive = "/dev/disk/by-id/nvme-eui.002538d221b47b01";
         };
-        extraCfg = testCfg;
       };
     };
   };

nix/modules/desktop/default.nix

@@ -0,0 +1,7 @@
+{ lib, ... }:
+let
+  inherit (lib.options) mkEnableOption;
+in
+{
+  flake.modules.nixos.default.options.desktop.enable = mkEnableOption "";
+}

nix/modules/machine/default.nix

@@ -11,8 +11,10 @@ in
     in
     {
       imports = [ (modulesPath + "/installer/scan/not-detected.nix") ];
-      options.machine.bluetooth.enable = mkEnableOption "";
-      options.machine.usb.automount = mkEnableOption "";
+      options.machine = {
+        bluetooth.enable = mkEnableOption "";
+        usb.automount = mkEnableOption "";
+      };
       config = mkMerge [
         (mkIf cfg.usb.automount {
           services.udisks2.enable = true;