all application options will adapt to environment

when used either with nixos (no home-manager) or home-manager standalone, `features.applications.<name>.enable` options still perform some functionality, rather than assuming a full nixos + home-manager setup like before

modules/features/applications/gui/spotify.nix

@@ -1,4 +1,26 @@
 { inputs, self, ... }: {
+  flake.nixosModules.graphics = { pkgs, config, lib, ... }: {
+    options.features.applications.gui.spotify = {
+      enable = lib.mkEnableOption "spotify";
+      spicetify.enable = lib.mkEnableOption "spicetify";
+    };
+
+    config = let
+      mkIfElse = with lib; p: yes: no:
+        mkMerge [
+          (mkIf p yes)
+          (mkIf (!p) no)
+        ];
+    in lib.mkIf (config.features.applications.gui.spotify.enable) (mkIfElse (config.features.nixos.home-manager.enable) {
+      home-manager.users.grey.features.applications.gui.spotify = {
+        enable = lib.mkDefault true;
+        spicetify.enable = lib.mkDefault config.features.applications.gui.spotify.spicetify.enable;
+      };
+    } {
+      environment.systemPackages = [ pkgs.spotify ];
+    });
+  };
+
   flake.homeModules.graphics = { pkgs, config, lib, ... }: {
     options.features.applications.gui.spotify = {
       enable = lib.mkEnableOption "spotify";
@@ -9,15 +31,13 @@
       inputs.spicetify.homeManagerModules.default
     ];
 
-    config = {
-      home.packages = lib.mkIf (with config.features.applications.gui.spotify; enable && !spicetify.enable) (with pkgs; [
-        spotify
-      ]);
+    config = lib.mkIf (config.features.applications.gui.spotify.enable) {
+      home.packages = lib.mkIf (!config.features.applications.gui.spotify.spicetify.enable) [ pkgs.spotify ];
 
       programs.spicetify =
       let
         spicePkgs = inputs.spicetify.legacyPackages.${pkgs.stdenv.hostPlatform.system};
-      in lib.mkIf (with config.features.applications.gui.spotify; enable && spicetify.enable) {
+      in lib.mkIf (config.features.applications.gui.spotify.spicetify.enable) {
         enable = true;
         enabledExtensions = with spicePkgs.extensions; [
           hidePodcasts