fix(trading): 交易记录金额单位从USDT改为积分值

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/mining-app/lib/presentation/pages/profile/trading_records_page.dart

@@ -286,7 +286,7 @@ class _TradingRecordsPageState extends ConsumerState<TradingRecordsPage> {
             mainAxisAlignment: MainAxisAlignment.spaceBetween,
             children: [
               _buildInfoItem('已成交', '${_formatQuantity(order.filledQuantity)} / ${_formatQuantity(order.quantity)}'),
-              _buildInfoItem('金额', '${_formatPrice(order.totalAmount)} USDT'),
+              _buildInfoItem('金额', '${_formatPrice(order.totalAmount)} 积分值'),
             ],
           ),
           const SizedBox(height: 8),