refactor(mako): use executable helper for history

configs/nixos/modules/desktop/session/mako.nix

@@ -5,24 +5,11 @@
   ...
 }:
 # mako as the notification daemon: toasts, a do-not-disturb mode, and history recall.
-let
-  user = config.user.name;
-
-  makoctl = "${pkgs.mako}/bin/makoctl";
-in
 {
   options.modules.desktop.session.mako.enable = lib.mkEnableOption "the mako notification daemon";
 
   config = lib.mkIf config.modules.desktop.session.mako.enable {
-    registry.keybind.${config.networking.hostName}.mako-history = {
-      keys = "SUPER + N";
-      action = {
-        kind = "exec";
-        command = "${makoctl} restore";
-      };
-    };
-
-    home-manager.users.${user} = {
+    home-manager.users.${config.user.name} = {
       # Colors and the popup font come from Stylix's mako target, so only
       # behaviour is set here.
       services.mako = {
@@ -39,7 +26,14 @@ in
           "mode=dnd".invisible = true;
         };
       };
+    };
 
+    registry.keybind.${config.networking.hostName}.mako-history = {
+      keys = "SUPER + N";
+      action = {
+        kind = "exec";
+        command = "${lib.getExe' pkgs.mako "makoctl"} restore";
+      };
     };
   };
 }