mpd: set default musicDirectory

modules/options/usrEnv/services/default.nix

@@ -1,6 +1,11 @@
-{lib, ...}: let
+{
+  config,
+  lib,
+  ...
+}: let
   inherit (lib.options) mkOption mkEnableOption;
   inherit (lib) types;
+  inherit (config.meta.mainUser) username;
 in {
   options.modules.usrEnv.services = {
     locate.enable = mkEnableOption "Locate service";
@@ -10,6 +15,7 @@ in {
         musicDirectory = mkOption {
           description = "music directory for mpd";
           type = types.str;
+          default = "/home/${username}/cloud/media/Music";
         };
       };
     };