fix: 为领奖与兑换流程添加分布式锁，防止并发重复操作

- 在 DailyTaskService 与 ActivationCodeService 中引入 Medallion.Threading。
- 通过 LazyServiceProvider 获取 IDistributedLockProvider（DistributedLock 属性）。
- 在 ClaimTaskRewardAsync（DailyTaskService）和 RedeemAsync（ActivationCodeService）中使用 AcquireLockAsync 加锁（基于 userId / activation code），用于自旋等待、防抖，避免并发导致的重复发放或重复兑换问题。

Yi.Abp.Net8/module/ai-hub/Yi.Framework.AiHub.Application/Services/ActivationCodeService.cs

@@ -1,3 +1,4 @@
+using Medallion.Threading;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 using Volo.Abp;
@@ -19,7 +20,7 @@ public class ActivationCodeService : ApplicationService, IActivationCodeService
     private readonly ActivationCodeManager _activationCodeManager;
     private readonly IRechargeService _rechargeService;
     private readonly PremiumPackageManager _premiumPackageManager;
-
+    private IDistributedLockProvider DistributedLock => LazyServiceProvider.LazyGetRequiredService<IDistributedLockProvider>();
     public ActivationCodeService(
         ActivationCodeManager activationCodeManager,
         IRechargeService rechargeService,
@@ -68,6 +69,10 @@ public class ActivationCodeService : ApplicationService, IActivationCodeService
     [HttpPost("activationCode/Redeem")]
     public async Task<ActivationCodeRedeemOutput> RedeemAsync(ActivationCodeRedeemInput input)
     {
+        //自旋等待，防抖
+        await using var handle =
+            await DistributedLock.AcquireLockAsync($"Yi:AiHub:ActivationCodeLock:{input.Code}");
+        
         var userId = CurrentUser.GetId();
         var redeemContext = await _activationCodeManager.RedeemAsync(userId, input.Code);
         var goodsType = redeemContext.ActivationCode.GoodsType;