fix: 延迟设置SSE响应头并兼容异常流数据

在成功获取第一条流式消息后再设置SSE响应头，避免无数据时提前建立连接；同时忽略异常类型的流消息，提升对部分AI工具的兼容性。

Yi.Abp.Net8/module/ai-hub/Yi.Framework.AiHub.Domain/Managers/AiGateWayManager.cs

@@ -612,10 +612,7 @@ public class AiGateWayManager : DomainService
         CancellationToken cancellationToken = default)
     {
         var response = httpContext.Response;
-        // 设置响应头，声明是 SSE 流
-        response.ContentType = "text/event-stream;charset=utf-8;";
-        response.Headers.TryAdd("Cache-Control", "no-cache");
-        response.Headers.TryAdd("Connection", "keep-alive");
+        // 注意：SSE响应头推迟到第一条消息成功获取后再设置
 
         _specialCompatible.AnthropicCompatible(request);
         var modelDescribe = await GetModelAsync(ModelApiTypeEnum.Messages, request.Model);
@@ -631,10 +628,25 @@ public class AiGateWayManager : DomainService
 
         var completeChatResponse = chatService.StreamChatCompletionsAsync(modelDescribe, request, cancellationToken);
         ThorUsageResponse? tokenUsage = new ThorUsageResponse();
+        bool isFirst = true;
         try
         {
             await foreach (var responseResult in completeChatResponse)
             {
+                // 第一条消息成功获取，才设置 SSE 响应头
+                if (isFirst)
+                {
+                    response.ContentType = "text/event-stream;charset=utf-8;";
+                    response.Headers.TryAdd("Cache-Control", "no-cache");
+                    response.Headers.TryAdd("Connection", "keep-alive");
+                    isFirst = false;
+                }
+
+                if (responseResult.Item1=="exception")
+                {
+                    //兼容部分ai工具问题
+                    continue;
+                }
                 //部分供应商message_start放一部分
                 if (responseResult.Item1.Contains("message_start"))
                 {