yarn: add session for steam

etcnixos/common.nix

@@ -49,13 +49,44 @@
     enable = true;
     settings = {
       default_session = {
-        command = "${lib.getExe pkgs.tuigreet} --sessions --time";
+        command = "${lib.getExe pkgs.tuigreet} --sessions /etc/xdg/wayland-sessions/ --time";
         user = username;
       };
       terminal.vt = lib.mkForce 2;
     };
   };
 
+  # Create steam session script
+  environment.etc."steam-session-greetd".source = pkgs.writeShellScript "steam-session-greetd" ''
+    export STEAM_RUNTIME=1
+    export SDL_VIDEODRIVER=wayland
+    export QT_QPA_PLATFORM=wayland
+    export GDK_BACKEND=wayland
+    export XDG_CURRENT_DESKTOP=Steam
+    export XDG_SESSION_TYPE=wayland
+    export MANGOHUD=1
+    exec ${pkgs.gamescope}/bin/gamescope --adaptive-sync --hdr-enabled --mangoapp --rt --steam -- ${pkgs.steam}/bin/steam -pipewire-dmabuf -tenfoot
+  '';
+
+  # Create system-wide session files
+  environment.etc."xdg/wayland-sessions/steam-session.desktop".text = ''
+    [Desktop Entry]
+    Name=Steam Session
+    Comment=Steam Deck-like gaming session with gamescope
+    Exec=/etc/steam-session-greetd
+    Type=Application
+    DesktopNames=steam
+  '';
+
+  environment.etc."xdg/wayland-sessions/niri-session.desktop".text = ''
+    [Desktop Entry]
+    Name=Niri Session
+    Comment=Niri Wayland compositor
+    Exec=${pkgs.niri}/bin/niri-session
+    Type=Application
+    DesktopNames=niri
+  '';
+
   system.activationScripts = {
     # FIX: https://github.com/NixOS/nix/issues/2982
     "profile-channel-dummy".text = ''

etcnixos/steam.nix

@@ -21,5 +21,8 @@
 
   environment.systemPackages = with pkgs; [
     steamtinkerlaunch
+    mangohud
+    goverlay
+    yad
   ];
 }

home-manager/home-yarn.nix

@@ -71,26 +71,6 @@
     '')
   ];
 
-  # Create desktop entry for Steam session
-  xdg.dataFile."wayland-sessions/steam-session.desktop".text = ''
-    [Desktop Entry]
-    Name=Steam Session
-    Comment=Steam Deck-like gaming session with gamescope
-    Exec=${config.home.homeDirectory}/.nix-profile/bin/steam-session-greetd
-    Type=Application
-    DesktopNames=steam
-  '';
-
-  # Create desktop entry for Niri session
-  xdg.dataFile."wayland-sessions/niri-session.desktop".text = ''
-    [Desktop Entry]
-    Name=Niri Session
-    Comment=Niri Wayland compositor
-    Exec=${config.programs.niri.package}/bin/niri-session
-    Type=Application
-    DesktopNames=niri
-  '';
-
   programs.obs-studio = {
     enable = true;
     plugins = with pkgs.obs-studio-plugins; [