feat(home-manager): service defs and fmt

fmt: reformatted using nixpkgs-fmt prettifier
mpd: created configuration
hypr: add window rules
commons: add usingMusicPlayerDaemon variable

home-manager/stvnliu/spicetify.nix

@@ -1,11 +1,12 @@
-{
-  pkgs,
-  lib,
-  inputs,
-  ...
-}: let
+{ pkgs
+, lib
+, inputs
+, ...
+}:
+let
   spicePkgs = inputs.spicetify-nix.legacyPackages.${pkgs.system};
-in {
+in
+{
   # allow spotify to be installed if you don't have unfree enabled already
   nixpkgs.config.allowUnfreePredicate = pkg:
     builtins.elem (lib.getName pkg) [