add gaming

modules/desktop/gaming/steam/default.nix

@@ -0,0 +1,20 @@
+{
+  pkgs,
+  lib,
+  config,
+  ...
+}: let
+  cfg = config.gaming.steam;
+in {
+  options.gaming.steam = {
+    enable = lib.mkEnableOption "enable steam";
+  };
+
+  config = lib.mkIf cfg.enable {
+    programs.steam = {
+      enable = true;
+      # requires setting launch option `gamescope %command%`
+      gamescopeSession.enable = true;
+    };
+  };
+}