fix

systems/x86_64-linux/steamdeck/default.nix

@@ -1,5 +1,6 @@
 {
   lib,
+  pkgs,
   namespace,
   ...
 }:
@@ -24,6 +25,9 @@
   };
 
   environment = {
+    systemPackages = with pkgs; [
+      # unigine-superposition
+    ];
     variables = {
       STEAM_FORCE_DESKTOPUI_SCALING = "1.0";
       GDK_SCALE = "1";