feat: enhance plugin management

- Add command support for plugin management
- Optimize plugin management page layout
- Add email copy functionality for users
- Convert payment methods and Telegram Bot to plugin system

app/Utils/Helper.php

@@ -7,8 +7,6 @@ use Illuminate\Support\Arr;
 
 class Helper
 {
-    private static $subscribeUrlCache = null;
-
     public static function uuidToBase64($uuid, $length)
     {
         return base64_encode(substr($uuid, 0, $length));