feat: UniqueConst에 숨겨진 hiddenSeed 생성

- 이후 RNG에 사용

hwe/d_setting/UniqueConst.orig.php

@@ -5,6 +5,7 @@ class UniqueConst{
     public static $serverID = '_tK_serverID_';
     public static $serverName = '_tK_serverName_';
     public static $seasonIdx = '_tK_seasonIdx_';
+    public static $hiddenSeed = '_tK_hiddenSeed_';
 
     private function __construct(){}