mango,steam,appimage: Improve integrations

modules/system/apps/steam.nix

@@ -11,10 +11,19 @@ in
     '';
   };
   config = mkIf cfg.enable {
+    programs.steam.gamescopeSession.enable = true;
     programs.steam = {
       enable = true;
+      package = pkgs.steam.override {
+        extraEnv = {
+          MANGOHUD = true;
+          OBS_VKCAPTURE = true;
+        };
+      };
       extraPackages = with pkgs; [ gamescope ];
       extraCompatPackages = with pkgs; [ proton-ge-bin ];
+      remotePlay.openFirewall = true;
+      localNetworkGameTransfers.openFirewall = true;
     };
 
     hardware.steam-hardware.enable = true;

modules/system/common.nix

@@ -72,10 +72,19 @@
     aha
     usbutils
     pciutils
-
-    appimage-run
+    mangohud
   ];
 
+  programs.appimage = {
+    enable = true;
+    binfmt = true;
+  };
+
+  environment.sessionVariables = {
+    STEAM_EXTRA_COMPAT_TOOLS_PATHS = "\${HOME}/.steam/root/compatibilitytools.d";
+    MANGOHUD_CONFIG = ''control=mangohud,legacy_layout=0,vertical,background_alpha=0,gpu_stats,gpu_power,cpu_stats,core_load,ram,vram,fps,fps_metrics=AVG,0.001,frametime,refresh_rate,resolution,gpu_name,vulkan_driver,wine'';
+  };
+
   services.fwupd.enable = true;
 
   # Define a user account. Don't forget to set a password with ‘passwd’.