added steam nixos module

modules/hosts/john-p14s/default.nix

@@ -22,6 +22,7 @@
       sudo
       john
       gnome
+      steam
       # greetd
       # niri
     ]);

modules/programs/steam.nix

@@ -0,0 +1,14 @@
+{ self, inputs, ... }: {
+  flake.modules.nixos.steam = {
+    programs.steam = {
+      enable = true;
+      gamescopeSession.enable = true;
+      # Open ports in the firewall for Steam Remote Play
+      remotePlay.openFirewall = true;
+      # Open ports in the firewall for Source Dedicated Server
+      dedicatedServer.openFirewall = true;
+      # Open ports in the firewall for Steam Local Network Game Transfers
+      localNetworkGameTransfers.openFirewall = true;
+    };
+  };
+}