Persist one browser user agent for Axios and WebSockets

lib/dxtrade-class.ts

@@ -31,7 +31,7 @@
  *   account shows as accountStatus ≠ FULL_TRADING → active=false.
  */
 
-import axios from 'axios';
+import axios from './http-client';
 import { currentTradeDateCT, FIRM_RESET_UTC_HOUR, DEFAULT_TARGET_HOLD_HOURS, rankForTarget } from './trading-logic';
 import {
     saveDailyPnL, loadDailyPnL, loadAccountMeta, saveAccountMeta, loadFundTransactions, saveFundTransactions,