desktop-jovian: unify steam/jovian config across yarn + patiodeck

- modules/desktop-jovian.nix: shared Jovian deck-mode config (unfree
  predicate, jovian.steam, sddm, gamescope override, imports
  desktop-steam-update.nix)
- home/progs/steam-shortcuts.nix: declarative non-Steam shortcuts
  (Prism Launcher); add new entries here for all Jovian hosts
- hosts/yarn/default.nix: reduced to host-specific config only
- hosts/patiodeck/default.nix: same

home/progs/steam-shortcuts.nix

@@ -0,0 +1,29 @@
+# Declarative non-Steam game shortcuts for the Steam library.
+# Add entries to the `shortcuts` list to have them appear in Steam's UI.
+{
+  pkgs,
+  inputs,
+  lib,
+  ...
+}:
+{
+  imports = [
+    inputs.json2steamshortcut.homeModules.default
+  ];
+
+  services.steam-shortcuts = {
+    enable = true;
+    overwriteExisting = true;
+    steamUserId = lib.strings.toInt (
+      lib.strings.trim (builtins.readFile ../../secrets/home/steam-user-id)
+    );
+    shortcuts = [
+      {
+        AppName = "Prism Launcher";
+        Exe = "${pkgs.prismlauncher}/bin/prismlauncher";
+        Icon = "${pkgs.prismlauncher}/share/icons/hicolor/scalable/apps/org.prismlauncher.PrismLauncher.svg";
+        Tags = [ "Game" ];
+      }
+    ];
+  };
+}

hosts/patiodeck/default.nix

@@ -1,6 +1,4 @@
 {
-  pkgs,
-  lib,
   username,
   inputs,
   site_config,
@@ -9,12 +7,11 @@
 {
   imports = [
     ../../modules/desktop-common.nix
-    ../../modules/desktop-steam-update.nix
+    ../../modules/desktop-jovian.nix
     ./disk.nix
     ./impermanence.nix
 
     inputs.impermanence.nixosModules.impermanence
-    inputs.jovian-nixos.nixosModules.default
   ];
 
   networking.hostId = "a1b2c3d4";
@@ -37,30 +34,5 @@
     site_config.ssh_keys.laptop
   ];
 
-  nixpkgs.config.allowUnfreePredicate =
+  jovian.devices.steamdeck.enable = true;
-    pkg:
-    builtins.elem (lib.getName pkg) [
-      "steamdeck-hw-theme"
-      "steam-jupiter-unwrapped"
-      "steam"
-      "steam-original"
-      "steam-unwrapped"
-      "steam-run"
-    ];
-
-  jovian = {
-    devices.steamdeck.enable = true;
-    steam = {
-      enable = true;
-      autoStart = true;
-      desktopSession = "niri";
-      user = username;
-    };
-  };
-
-  # Jovian-NixOS requires sddm
-  services.displayManager.sddm.wayland.enable = true;
-
-  # disable gamescope from desktop-common.nix to avoid conflict with jovian
-  programs.gamescope.enable = lib.mkForce false;
 }

hosts/patiodeck/home.nix

@@ -1,29 +1,8 @@
-{
+{ ... }:
-  pkgs,
-  inputs,
-  lib,
-  ...
-}:
 {
   imports = [
     ../../home/profiles/gui.nix
     ../../home/profiles/desktop.nix
-    inputs.json2steamshortcut.homeModules.default
+    ../../home/progs/steam-shortcuts.nix
   ];
-
-  services.steam-shortcuts = {
-    enable = true;
-    overwriteExisting = true;
-    steamUserId = lib.strings.toInt (
-      lib.strings.trim (builtins.readFile ../../secrets/home/steam-user-id)
-    );
-    shortcuts = [
-      {
-        AppName = "Prism Launcher";
-        Exe = "${pkgs.prismlauncher}/bin/prismlauncher";
-        Icon = "${pkgs.prismlauncher}/share/icons/hicolor/scalable/apps/org.prismlauncher.PrismLauncher.svg";
-        Tags = [ "Game" ];
-      }
-    ];
-  };
 }

hosts/yarn/default.nix

@@ -1,5 +1,4 @@
 {
-  config,
   pkgs,
   lib,
   username,
@@ -10,14 +9,13 @@
 {
   imports = [
     ../../modules/desktop-common.nix
-    ../../modules/desktop-steam-update.nix
+    ../../modules/desktop-jovian.nix
     ../../modules/no-rgb.nix
     ./disk.nix
     ./impermanence.nix
     ./vr.nix
 
     inputs.impermanence.nixosModules.impermanence
-    inputs.jovian-nixos.nixosModules.default
   ];
 
   fileSystems."/media/games" = {
@@ -84,31 +82,6 @@
 
   systemd.services.lactd.serviceConfig.ExecStartPre = "${lib.getExe pkgs.bash} -c \"sleep 3s\"";
 
-  nixpkgs.config.allowUnfreePredicate =
+  # yarn is not a Steam Deck
-    pkg:
+  jovian.devices.steamdeck.enable = false;
-    builtins.elem (lib.getName pkg) [
-      "steamdeck-hw-theme"
-      "steam-jupiter-unwrapped"
-      "steam"
-      "steam-original"
-      "steam-unwrapped"
-      "steam-run"
-    ];
-
-  jovian = {
-    devices.steamdeck.enable = false;
-    steam = {
-      enable = true;
-      autoStart = true;
-      desktopSession = "niri";
-      user = username;
-    };
-  };
-
-  # Jovian-NixOS requires sddm
-  # https://github.com/Jovian-Experiments/Jovian-NixOS/commit/52f140c07493f8bb6cd0773c7e1afe3e1fd1d1fa
-  services.displayManager.sddm.wayland.enable = true;
-
-  # Disable gamescope from common.nix to avoid conflict with jovian-nixos
-  programs.gamescope.enable = lib.mkForce false;
 }

hosts/yarn/home.nix

@@ -1,15 +1,12 @@
 {
   pkgs,
-  inputs,
-  lib,
-  config,
   ...
 }:
 {
   imports = [
     ../../home/profiles/gui.nix
     ../../home/profiles/desktop.nix
-    inputs.json2steamshortcut.homeModules.default
+    ../../home/progs/steam-shortcuts.nix
   ];
 
   home.packages = with pkgs; [
@@ -27,20 +24,4 @@
       obs-pipewire-audio-capture
     ];
   };
-
-  services.steam-shortcuts = {
-    enable = true;
-    overwriteExisting = true;
-    steamUserId = lib.strings.toInt (
-      lib.strings.trim (builtins.readFile ../../secrets/home/steam-user-id)
-    );
-    shortcuts = [
-      {
-        AppName = "Prism Launcher";
-        Exe = "${pkgs.prismlauncher}/bin/prismlauncher";
-        Icon = "${pkgs.prismlauncher}/share/icons/hicolor/scalable/apps/org.prismlauncher.PrismLauncher.svg";
-        Tags = [ "Game" ];
-      }
-    ];
-  };
 }

modules/desktop-jovian.nix

@@ -0,0 +1,40 @@
+# Jovian-NixOS deck-mode configuration shared by all hosts running Steam
+# in gamescope (yarn, patiodeck). Host-specific settings (like
+# jovian.devices.steamdeck.enable) stay in the host's default.nix.
+{
+  lib,
+  username,
+  inputs,
+  ...
+}:
+{
+  imports = [
+    ./desktop-steam-update.nix
+    inputs.jovian-nixos.nixosModules.default
+  ];
+
+  nixpkgs.config.allowUnfreePredicate =
+    pkg:
+    builtins.elem (lib.getName pkg) [
+      "steamdeck-hw-theme"
+      "steam-jupiter-unwrapped"
+      "steam"
+      "steam-original"
+      "steam-unwrapped"
+      "steam-run"
+    ];
+
+  jovian.steam = {
+    enable = true;
+    autoStart = true;
+    desktopSession = "niri";
+    user = username;
+  };
+
+  # jovian overrides the display manager; sddm is required
+  services.displayManager.sddm.wayland.enable = true;
+
+  # desktop-common.nix enables programs.gamescope which conflicts with
+  # jovian's own gamescope wrapper
+  programs.gamescope.enable = lib.mkForce false;
+}