refactor: Move sw into properly nested modules with unconditional import

sw/desktop/default.nix

@@ -10,21 +10,50 @@
   inputs,
   ...
 }:
-lib.mkMerge [
-  (import ./programs.nix {
-    inherit
-      config
-      lib
-      pkgs
-      inputs
-      ;
-  })
-  (import ./services.nix {
-    inherit
-      config
-      lib
-      pkgs
-      inputs
-      ;
-  })
-]
+
+with lib;
+
+let
+  cfg = config.athenix.sw.desktop;
+in
+{
+  options.athenix.sw.desktop = {
+    enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Enable full desktop environment with KDE Plasma 6.
+
+        Includes:
+        - KDE Plasma 6 desktop with SDDM display manager
+        - Full graphical software suite (Firefox, Chromium, LibreOffice)
+        - Printing and scanning support (CUPS)
+        - Virtualization (libvirt, virt-manager)
+        - Bluetooth and audio (PipeWire)
+        - Video conferencing (Zoom, Teams)
+
+        Recommended for: Workstations, development machines, user desktops
+      '';
+      example = true;
+    };
+  };
+
+  config = mkIf cfg.enable (mkMerge [
+    (import ./programs.nix {
+      inherit
+        config
+        lib
+        pkgs
+        inputs
+        ;
+    })
+    (import ./services.nix {
+      inherit
+        config
+        lib
+        pkgs
+        inputs
+        ;
+    })
+  ]);
+}