fix(wallet): 提现失败解冻时优先使用 accountSequence 查找钱包

问题背景:
- 原实现使用 userId 查找钱包进行解冻操作
- userId 来自外部 identity-service，存在变化风险
- 如果 userId 发生变化，可能导致解冻到错误的钱包

解决方案:
- 优先使用 accountSequence 查找钱包（wallet-service 内部主键，稳定可靠）
- 保留 userId 作为兜底查找方式，确保向后兼容
- 增加钱包找不到时的详细错误日志

改动点:
- withdrawal-status.handler.ts: handleWithdrawalFailed() 方法
- 与认种(planting)的钱包查找逻辑保持一致

🤖 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/event-handlers/withdrawal-status.handler.ts

@@ -103,12 +103,19 @@ export class WithdrawalStatusHandler implements OnModuleInit {
 
       // Refund frozen funds back to available balance if needed
       if (order.needsUnfreeze()) {
-        const wallet = await this.walletRepo.findByUserId(order.userId.value);
+        // 优先使用 accountSequence 查找钱包（更可靠，避免 userId 变化导致扣错人）
+        let wallet = await this.walletRepo.findByAccountSequence(order.accountSequence);
+        if (!wallet) {
+          // 兜底：使用 userId 查找
+          wallet = await this.walletRepo.findByUserId(order.userId.value);
+        }
         if (wallet) {
           // Unfreeze the amount (add back to available balance)
           wallet.unfreeze(order.amount);
           await this.walletRepo.save(wallet);
-          this.logger.log(`[FAILED] Refunded ${order.amount.value} USDT to user ${order.userId}`);
+          this.logger.log(`[FAILED] Refunded ${order.amount.value} USDT to account ${order.accountSequence}`);
+        } else {
+          this.logger.error(`[FAILED] Wallet not found for accountSequence: ${order.accountSequence}, userId: ${order.userId}`);
         }
       }