feat: 新增海外站点流量限制和CORS配置优化

- 新增yxai.chat域名到CORS白名单
- 为海外站点yxai.chat添加大流量接口访问限制
- 修复Azure OpenAI图像生成服务默认尺寸设置

Yi.Abp.Net8/module/ai-hub/Yi.Framework.AiHub.Domain/AiGateWay/Impl/ThorAzureOpenAI/Images/AzureOpenAIServiceImageService.cs

@@ -13,7 +13,7 @@ public class AzureOpenAIServiceImageService : IImageService
         var createClient = AzureOpenAIFactory.CreateClient(options);
 
         var client = createClient.GetImageClient(imageCreate.Model);
-
+        imageCreate.Size??="1024x1024";
         // 将size字符串拆分为宽度和高度
         var size = imageCreate.Size.Split('x');
         if (size.Length != 2)