refactor(steam): configure SteamVR with Steam

configs/nixos/hosts/zeus/default.nix

@@ -1,15 +1,11 @@
 {
   config,
   lib,
-  pkgs,
   ...
 }:
 # zeus — Ryzen desktop with AMD graphics.
 # Disk layout is in ./disk.nix.
 # `fileSystems` are derived from it, none declared here.
-let
-  steamVrLauncher = "/home/${config.user.name}/.local/share/Steam/steamapps/common/SteamVR/bin/linux64/vrcompositor-launcher";
-in
 {
   imports = [
     ./disk.nix
@@ -53,27 +49,6 @@ in
   modules.desktop.apps.steam.enable = true;
   modules.desktop.apps.vencord.enable = true;
 
-  networking.firewall.allowedUDPPorts = [ 10400 ];
-
-  programs.gamescope.capSysNice = true;
-
-  systemd.paths.steamvr-capabilities = {
-    wantedBy = [ "multi-user.target" ];
-    pathConfig = {
-      PathChanged = steamVrLauncher;
-      Unit = "steamvr-capabilities.service";
-    };
-  };
-
-  systemd.services.steamvr-capabilities = {
-    wantedBy = [ "multi-user.target" ];
-    path = [ pkgs.libcap ];
-    script = ''
-      setcap cap_sys_nice=eip ${lib.escapeShellArg steamVrLauncher}
-    '';
-    serviceConfig.Type = "oneshot";
-  };
-
   home-manager.users.${config.user.name}.wayland.windowManager.hyprland.settings.monitor = [
     {
       output = "HDMI-A-1";

configs/nixos/modules/desktop/apps/steam.nix

@@ -6,6 +6,9 @@
   ...
 }:
 # Steam game launcher and runtime integration.
+let
+  steamVrLauncher = "/home/${config.user.name}/.local/share/Steam/steamapps/common/SteamVR/bin/linux64/vrcompositor-launcher";
+in
 {
   options.modules.desktop.apps.steam.enable = lib.mkEnableOption "Steam game launcher";
 
@@ -21,7 +24,29 @@
 
     hardware.steam-hardware.enable = true;
 
-    programs.gamescope.enable = true;
+    programs.gamescope = {
+      enable = true;
+      capSysNice = true;
+    };
+
+    networking.firewall.allowedUDPPorts = [ 10400 ];
+
+    systemd.paths.steamvr-capabilities = {
+      wantedBy = [ "multi-user.target" ];
+      pathConfig = {
+        PathChanged = steamVrLauncher;
+        Unit = "steamvr-capabilities.service";
+      };
+    };
+
+    systemd.services.steamvr-capabilities = {
+      wantedBy = [ "multi-user.target" ];
+      path = [ pkgs.libcap ];
+      script = ''
+        setcap cap_sys_nice=eip ${lib.escapeShellArg steamVrLauncher}
+      '';
+      serviceConfig.Type = "oneshot";
+    };
 
     registry.window-icon.${config.networking.hostName}.steam = {
       class = "[Ss]team";