feat(wallet-service): allocateFunds 添加幂等性检查

防止重复分配奖励，通过检查流水表中的 orderId + accountSequence + allocationType 组合

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/services/wallet-service/src/application/services/wallet-application.service.ts

@@ -898,9 +898,26 @@ export class WalletApplicationService {
 
     let totalAmount = 0;
     let allocatedCount = 0;
+    let skippedCount = 0;
 
     for (const allocation of command.allocations) {
       try {
+        // 幂等性检查：检查该订单+账户+分配类型是否已分配
+        const alreadyAllocated = await this.checkAllocationExists(
+          command.orderId,
+          allocation.targetId,
+          allocation.allocationType,
+        );
+
+        if (alreadyAllocated) {
+          this.logger.warn(
+            `[IDEMPOTENT] Allocation already exists for order ${command.orderId}, ` +
+            `target ${allocation.targetId}, type ${allocation.allocationType}. Skipping.`,
+          );
+          skippedCount++;
+          continue;
+        }
+
         if (allocation.targetType === 'USER') {
           // 分配给用户钱包
           await this.allocateToUserWallet(allocation, command.orderId);
@@ -920,16 +937,41 @@ export class WalletApplicationService {
     }
 
     this.logger.log(
-      `Allocated ${allocatedCount}/${command.allocations.length} items, total ${totalAmount} USDT`,
+      `Allocated ${allocatedCount}/${command.allocations.length} items (skipped ${skippedCount}), total ${totalAmount} USDT`,
     );
 
     return {
-      success: allocatedCount > 0,
+      success: allocatedCount > 0 || skippedCount > 0,
       allocatedCount,
       totalAmount,
     };
   }
 
+  /**
+   * 检查分配是否已存在（幂等性检查）
+   * 通过查询流水表判断该订单+账户+分配类型是否已处理
+   */
+  private async checkAllocationExists(
+    orderId: string,
+    targetId: string,
+    allocationType: string,
+  ): Promise<boolean> {
+    // 查询流水表，检查是否已存在该订单的分配记录
+    // 流水的 payloadJson 中存储了 allocationType
+    const existingEntry = await this.prisma.ledgerEntry.findFirst({
+      where: {
+        refOrderId: orderId,
+        accountSequence: targetId,
+        payloadJson: {
+          path: ['allocationType'],
+          equals: allocationType,
+        },
+      },
+    });
+
+    return !!existingEntry;
+  }
+
   /**
    * 分配资金到用户钱包
    * 支持用户账户 (D+日期+序号) 和系统账户 (S+序号, 7+省代码, 6+市代码, 9+省代码, 8+市代码)