feat: 消息创建返回ID并在流式响应中下发

- 消息管理器创建用户/系统消息时返回 MessageId
- 网关在流式响应中新增消息创建事件，返回 MessageId 与创建时间
- 统一在消息创建完成后发送 [DONE] 标识，优化流式结束时机

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

@@ -23,6 +23,7 @@ using Yi.Framework.AiHub.Domain.Shared.Dtos.OpenAi.Embeddings;
 using Yi.Framework.AiHub.Domain.Shared.Dtos.OpenAi.Images;
 using Yi.Framework.AiHub.Domain.Shared.Dtos.OpenAi.Responses;
 using Yi.Framework.AiHub.Domain.Shared.Enums;
+using Yi.Framework.AiHub.Application.Contracts.Dtos.Chat;
 using Yi.Framework.AiHub.Domain.Shared.Extensions;
 using Yi.Framework.Core.Extensions;
 using Yi.Framework.SqlSugarCore.Abstractions;
@@ -1207,12 +1208,9 @@ public class AiGateWayManager : DomainService
                 throw new UserFriendlyException($"不支持的API类型: {apiType}");
         }
         
-        // 标记完成并等待消费任务结束
-        isComplete = true;
-        await outputTask;
-
+        
         // 统一的统计处理
-        await _aiMessageManager.CreateUserMessageAsync(userId, sessionId,
+        var userMessageId = await _aiMessageManager.CreateUserMessageAsync(userId, sessionId,
             new MessageInputDto
             {
                 Content = sessionId is null ? "不予存储" : processResult?.UserContent ?? string.Empty,
@@ -1220,7 +1218,7 @@ public class AiGateWayManager : DomainService
                 TokenUsage = processResult?.TokenUsage,
             }, tokenId,createTime:startTime);
 
-        await _aiMessageManager.CreateSystemMessageAsync(userId, sessionId,
+        var systemMessageId = await _aiMessageManager.CreateSystemMessageAsync(userId, sessionId,
             new MessageInputDto
             {
                 Content = sessionId is null ? "不予存储" : processResult?.SystemContent ?? string.Empty,
@@ -1228,6 +1226,29 @@ public class AiGateWayManager : DomainService
                 TokenUsage = processResult?.TokenUsage
             }, tokenId);
 
+        // 流式返回消息ID
+        var now = DateTime.Now;
+        var userMessageOutput = new MessageCreatedOutput
+        {
+            TypeEnum = ChatMessageTypeEnum.UserMessage,
+            MessageId = userMessageId,
+            CreationTime = startTime
+        };
+        messageQueue.Enqueue($"data: {JsonSerializer.Serialize(userMessageOutput, ThorJsonSerializer.DefaultOptions)}\n\n");
+
+        var systemMessageOutput = new MessageCreatedOutput
+        {
+            TypeEnum = ChatMessageTypeEnum.SystemMessage,
+            MessageId = systemMessageId,
+            CreationTime = now
+        };
+        messageQueue.Enqueue($"data: {JsonSerializer.Serialize(systemMessageOutput, ThorJsonSerializer.DefaultOptions)}\n\n");
+
+        // 标记完成并等待消费任务结束
+        messageQueue.Enqueue("data: [DONE]\n\n");
+        isComplete = true;
+        await outputTask;
+        
         await _usageStatisticsManager.SetUsageAsync(userId, sourceModelId, processResult?.TokenUsage, tokenId);
 
         // 扣减尊享token包用量
@@ -1325,8 +1346,7 @@ public class AiGateWayManager : DomainService
             });
             messageQueue.Enqueue($"data: {errorMessage}\n\n");
         }
-
-        messageQueue.Enqueue("data: [DONE]\n\n");
+        
         return new StreamProcessResult
         {
             UserContent = userContent,