fix: 佣金按委托级合并计费（分笔成交只收一次佣金）

- calcOrderFees 委托层合并计费：同一委托分笔成交按总金额算一次佣金（最低5元一次）
- mapTrade 保留原始成交字段，不再逐笔算费
- 前端聚合调用 calcOrderFees，展开明细只展示成交本身
- 验证：200股拆两笔佣金5元（非10元）；两笔独立委托各5元

src/client/views/TradeRecordsTab.jsx

@@ -48,6 +48,23 @@ function directionText(direction) {
   return '—';
 }
 
+/** 费用计算：按整笔委托合并（同一委托分笔成交只收一次佣金，最低5元；2026-09-01 老师修正） */
+function calcOrderFeesLocal(trades, commissionRateWan) {
+  const list = Array.isArray(trades) ? trades : [];
+  const totalAmount = list.reduce((s, t) => s + Math.max(0, +(t.amount ?? 0)), 0);
+  const direction = list[0]?.direction ?? '';
+  let commission = totalAmount * (commissionRateWan / 10000);
+  if (commission < 5 && commission > 0) commission = 5;
+  const stampTax = direction === 'sell' ? totalAmount * 0.0005 : 0;
+  const transferFee = totalAmount * 0.00001;
+  return {
+    commission: +commission.toFixed(4),
+    stampTax: +stampTax.toFixed(4),
+    transferFee: +transferFee.toFixed(4),
+    total: +(commission + stampTax + transferFee).toFixed(4),
+  };
+}
+
 /** 合并逻辑：按 m_strOrderSysID 把成交聚合进委托 */
 function mergeOrdersAndTrades(orders, trades) {
   const tradeByOrder = new Map();
@@ -59,24 +76,22 @@ function mergeOrdersAndTrades(orders, trades) {
     const ts = tradeByOrder.get(o.orderId) ?? [];
     const totalVol = ts.reduce((s, t) => s + t.volume, 0);
     const totalAmount = ts.reduce((s, t) => s + t.amount, 0);
-    // 费用逐笔计算后聚合（每笔 commission/stampTax/transferFee 已是金额）
-    const aggCommission = ts.reduce((s, t) => s + t.commission, 0);
-    const aggStampTax = ts.reduce((s, t) => s + t.stampTax, 0);
-    const aggTransferFee = ts.reduce((s, t) => s + t.transferFee, 0);
-    const aggFeeTotal = ts.reduce((s, t) => s + t.feeTotal, 0);
     const weightedPrice = totalVol > 0
       ? ts.reduce((s, t) => s + t.price * t.volume, 0) / totalVol
       : 0;
+    // 费用：按整笔委托合并计算（同一委托分笔成交只收一次佣金，calcOrderFees）
+    const rateWan = ts[0]?.commissionRateWan ?? 0; // 佣金费率（万分之，来自成交，账号级一致）
+    const fees = calcOrderFeesLocal(ts, rateWan);
     return {
       ...o,
       trades: ts,
       aggVolume: totalVol,
       aggPrice: weightedPrice,
       aggAmount: totalAmount,
-      aggCommission,
-      aggStampTax,
-      aggTransferFee,
-      aggFeeTotal,
+      aggCommission: fees.commission,
+      aggStampTax: fees.stampTax,
+      aggTransferFee: fees.transferFee,
+      aggFeeTotal: fees.total,
     };
   });
 }
@@ -288,10 +303,6 @@ function OrderRows({ order, expanded, onToggle }) {
                   <th style={{ ...tdStyle, textAlign: 'right' }}>成交价</th>
                   <th style={{ ...tdStyle, textAlign: 'right' }}>成交量</th>
                   <th style={{ ...tdStyle, textAlign: 'right' }}>成交额</th>
-                  <th style={{ ...tdStyle, textAlign: 'right' }}>总费用</th>
-                  <th style={{ ...tdStyle, textAlign: 'right' }}>佣金</th>
-                  <th style={{ ...tdStyle, textAlign: 'right' }}>印花税</th>
-                  <th style={{ ...tdStyle, textAlign: 'right' }}>过户费</th>
                   <th style={{ ...tdStyle, textAlign: 'right' }}>成交号</th>
                 </tr>
               </thead>
@@ -302,10 +313,6 @@ function OrderRows({ order, expanded, onToggle }) {
                     <td style={{ ...tdStyle, textAlign: 'right' }}>{fmtNum(t.price)}</td>
                     <td style={{ ...tdStyle, textAlign: 'right' }}>{fmtNum(t.volume, 0)}</td>
                     <td style={{ ...tdStyle, textAlign: 'right' }}>{fmtNum(t.amount)}</td>
-                    <td style={{ ...tdStyle, textAlign: 'right' }}>{fmtNum(t.feeTotal, 2)}</td>
-                    <td style={{ ...tdStyle, textAlign: 'right' }}>{fmtNum(t.commission, 2)}</td>
-                    <td style={{ ...tdStyle, textAlign: 'right' }}>{fmtNum(t.stampTax, 2)}</td>
-                    <td style={{ ...tdStyle, textAlign: 'right' }}>{fmtNum(t.transferFee, 2)}</td>
                     <td style={{ ...tdStyle, textAlign: 'right', color: '#999' }}>{t.tradeId}</td>
                   </tr>
                 ))}