fix: add isAdmin delegate method to AdminHandler, fix exportCSV call in adminWalletsHandler

- AdminHandler.isAdmin() static method delegates to middleware/auth.js
  (index.js calls adminHandler.isAdmin() which needs a class method)
- adminWalletsHandler: this.exportCSV() → this.handleExportCSV(callbackQuery)
  (exportCSV doesn't exist, handleExportCSV is the correct method)

src/handlers/adminHandlers/adminHandler.js

@@ -2,6 +2,10 @@ import { isAdmin } from '../../middleware/auth.js';
 import bot from "../../context/bot.js";
 
 export default class AdminHandler {
+    static isAdmin(userId) {
+        return isAdmin(userId);
+    }
+
     static async handleAdminCommand(msg) {
         const chatId = msg.chat.id;
 

src/handlers/adminHandlers/adminWalletsHandler.js

@@ -510,7 +510,8 @@ export default class AdminWalletsHandler {
             } else {
                 // Если баланс достаточный, продолжаем экспорт
                 console.log(`[${new Date().toISOString()}] Commission balance sufficient, proceeding with export`);
-                await this.exportCSV(chatId, walletType, wallets);
+                await this.handleExportCSV(callbackQuery);
+                return;
             }
         } catch (error) {
             console.error(`[${new Date().toISOString()}] Error checking commission balance:`, error);