misc improvements to modularity

modules/components/window-managers/niri.nix

@@ -35,7 +35,7 @@
         }));
       };
 
-      home-manager.users.grey = lib.mkIf (config.features.nixos.home-manager.enable) {
+      home-manager.users.${config.info.userName} = lib.mkIf (config.features.nixos.home-manager.enable) {
         components.windowManagers = [ "niri" ];
       };
     };