fix(flake): added global overlay for gamescope

nix/flake.nix

@@ -51,6 +51,24 @@
       ...
     }:
     let
+      overlays = [
+        (
+          final: prev:
+          let
+            system = prev.stdenv.hostPlatform.system;
+            pkgs_gamescope = import inputs.nixpkgs-gamescope {
+              inherit system;
+              config = {
+                allow_unfree = true;
+              };
+            };
+            packageNix = "${inputs.nixpkgs-gamescope}/pkgs/by-name/ga/gamescope/package.nix";
+          in
+          {
+            gamescope = pkgs_gamescope.callPackage packageNix { };
+          }
+        )
+      ];
       utils = nix-meow.lib.setup {
         inherit (inputs) home-manager nixpkgs;
         inherit inputs;
@@ -61,7 +79,7 @@
         globalConfig = {
           allowUnfree = true;
         };
-        globalOverlays = [ ];
+        globalOverlays = overlays;
         defaultUser = "doloro";
       };
       inherit (utils) mkHost;