feat: 新增消息软删除及批量隐藏接口

Yi.Abp.Net8/module/ai-hub/Yi.Framework.AiHub.Domain/Entities/Chat/MessageAggregateRoot.cs

@@ -75,4 +75,9 @@ public class MessageAggregateRoot : FullAuditedAggregateRoot<Guid>
     [SugarColumn(IsOwnsOne = true)] public TokenUsageValueObject TokenUsage { get; set; } = new TokenUsageValueObject();
 
     public MessageTypeEnum MessageType { get; set; }
+
+    /// <summary>
+    /// 是否隐藏（软删除标记，隐藏后不返回给前端）
+    /// </summary>
+    public bool IsHidden { get; set; } = false;
 }