fix(c2c): 修复过期恢复的竞态条件，SELL订单保持冻结避免资金窗口

- SELL MATCHED/PAID 订单过期恢复时，不再先解冻再重新冻结
- 保持 maker 的冻结不变，直接转给新 PENDING 订单
- 消除了解冻→重新冻结之间的竞态窗口（余额可能被其他操作消耗）
- 恢复失败时补充解冻，防止 maker 资金被永久冻结
- BUY 订单恢复时不复制上一个 taker 的 sellerKavaAddress

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

backend/services/trading-service/src/application/services/c2c.service.ts

@@ -723,6 +723,7 @@ export class C2cService {
       }
 
       const quantityDecimal = new Decimal(freshOrder.quantity);
+      const shouldRestore = freshOrder.status === C2C_ORDER_STATUS.MATCHED || freshOrder.status === C2C_ORDER_STATUS.PAID;
 
       // 解冻卖方的积分值（C2C交易的是积分值，买方不冻结）
       if (freshOrder.status === C2C_ORDER_STATUS.PENDING) {
@@ -736,8 +737,12 @@ export class C2cService {
         if (freshOrder.takerAccountSequence) {
           await this.tradingAccountRepository.unfreezeCash(freshOrder.takerAccountSequence, quantityDecimal);
         }
+      } else if (shouldRestore) {
+        // MATCHED/PAID SELL订单将恢复为新PENDING：保持maker的冻结不变
+        // 冻结资金直接转给新PENDING订单，避免 解冻→重新冻结 的竞态窗口
+        this.logger.log(`SELL订单 ${freshOrder.orderNo} 将恢复，保持冻结 ${quantityDecimal}`);
       } else {
-        // MATCHED/PAID: SELL订单解冻maker（卖方）的积分值
+        // MATCHED/PAID SELL订单不恢复时解冻maker（卖方）的积分值
         await this.tradingAccountRepository.unfreezeCash(freshOrder.makerAccountSequence, quantityDecimal);
       }
 
@@ -749,7 +754,7 @@ export class C2cService {
       this.logger.log(`C2C订单已过期: ${freshOrder.orderNo}, 原状态: ${freshOrder.status}`);
 
       // MATCHED/PAID 订单过期后，将数量退还为新的 PENDING 订单（恢复到市场）
-      if (freshOrder.status === C2C_ORDER_STATUS.MATCHED || freshOrder.status === C2C_ORDER_STATUS.PAID) {
+      if (shouldRestore) {
         await this.restoreExpiredOrder(freshOrder, quantityDecimal);
       }
     } finally {
@@ -760,26 +765,17 @@ export class C2cService {
   /**
    * 过期订单恢复：为 maker 重新创建一个 PENDING 订单
    * 将过期的成交数量退还到市场，让其他用户可以继续接单
+   *
+   * 注意：SELL 订单的冻结在 expireOrder 中已保持不变（未解冻），
+   * 直接转给新的 PENDING 订单，避免 解冻→重新冻结 的竞态条件。
    */
   private async restoreExpiredOrder(expiredOrder: C2cOrderEntity, quantityDecimal: Decimal): Promise<void> {
     try {
       const priceDecimal = new Decimal(expiredOrder.price);
       const totalAmountDecimal = priceDecimal.mul(quantityDecimal);
 
-      // SELL 订单需要重新冻结 maker 的积分值
-      if (expiredOrder.type === C2C_ORDER_TYPE.SELL) {
-        const makerAccount = await this.tradingAccountRepository.findByAccountSequence(expiredOrder.makerAccountSequence);
-        if (!makerAccount) {
-          this.logger.warn(`过期恢复: maker ${expiredOrder.makerAccountSequence} 账户不存在，跳过恢复`);
-          return;
-        }
-        const quantityMoney = new Money(quantityDecimal);
-        if (makerAccount.availableCash.isLessThan(quantityMoney)) {
-          this.logger.warn(`过期恢复: maker ${expiredOrder.makerAccountSequence} 可用余额不足 (需要 ${quantityDecimal}, 可用 ${makerAccount.availableCash})，跳过恢复`);
-          return;
-        }
-        await this.tradingAccountRepository.freezeCash(expiredOrder.makerAccountSequence, quantityDecimal);
-      }
+      // SELL 订单：冻结已在 expireOrder 中保留，无需重新冻结
+      // BUY 订单：无冻结，直接创建新 PENDING 订单
 
       // 创建新的 PENDING 订单
       const restoreOrderNo = this.generateOrderNo();
@@ -797,14 +793,22 @@ export class C2cService {
         paymentAccount: expiredOrder.type === C2C_ORDER_TYPE.SELL ? (expiredOrder.paymentAccount ?? undefined) : undefined,
         paymentQrCode: expiredOrder.type === C2C_ORDER_TYPE.SELL ? (expiredOrder.paymentQrCode ?? undefined) : undefined,
         paymentRealName: expiredOrder.type === C2C_ORDER_TYPE.SELL ? (expiredOrder.paymentRealName ?? undefined) : undefined,
-        sellerKavaAddress: expiredOrder.sellerKavaAddress,
+        sellerKavaAddress: expiredOrder.type === C2C_ORDER_TYPE.SELL ? (expiredOrder.sellerKavaAddress ?? undefined) : undefined,
         remark: expiredOrder.remark ?? undefined,
       });
 
       this.logger.log(`过期恢复: 订单 ${expiredOrder.orderNo} 已恢复为新 PENDING 订单 ${restoreOrderNo}, 数量: ${quantityDecimal}`);
     } catch (error) {
       this.logger.error(`过期恢复失败: ${expiredOrder.orderNo}`, error);
-      // 恢复失败不影响过期流程，只记录日志
+      // SELL 订单恢复失败时，需要解冻之前保留的冻结（否则 maker 资金被永久冻结）
+      if (expiredOrder.type === C2C_ORDER_TYPE.SELL) {
+        try {
+          await this.tradingAccountRepository.unfreezeCash(expiredOrder.makerAccountSequence, quantityDecimal);
+          this.logger.warn(`过期恢复失败，已解冻 ${quantityDecimal} for ${expiredOrder.makerAccountSequence}`);
+        } catch (unfreezeError) {
+          this.logger.error(`过期恢复失败后解冻也失败: ${expiredOrder.orderNo}`, unfreezeError);
+        }
+      }
     }
   }
 }