fix: 更新免费模型默认ID

将 FreeModelId 从 DeepSeek-V3 调整为 DeepSeek-V3-0324，确保使用最新可用的免费模型配置

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

@@ -50,7 +50,7 @@ public class AiChatService : ApplicationService
     private readonly IAccountService _accountService;
     private readonly ISqlSugarRepository<AgentStoreAggregateRoot> _agentStoreRepository;
     private readonly ISqlSugarRepository<AiModelEntity> _aiModelRepository;
-    private const string FreeModelId = "DeepSeek-V3";
+    private const string FreeModelId = "DeepSeek-V3-0324";
 
     public AiChatService(IHttpContextAccessor httpContextAccessor,
         AiBlacklistManager aiBlacklistManager,