fix:修复已知问题

backend/IM_API/Services/ConversationService.cs

@@ -42,7 +42,7 @@ namespace IM_API.Services
             var groupList = await (from c in _context.Conversations
                                    join g in _context.Groups on c.TargetId equals g.Id
                                    where c.UserId == userId && c.ChatType == ChatType.GROUP
-                                   select new { c, g.Avatar, g.Name })
+                                   select new { c, g.Avatar, g.Name,g.MaxSequenceId,g.LastMessage })
                                    .ToListAsync();
 
             var privateDtos = privateList.Select(x =>
@@ -58,6 +58,9 @@ namespace IM_API.Services
                 var dto = _mapper.Map<ConversationVo>(x.c);
                 dto.TargetAvatar = x.Avatar;
                 dto.TargetName = x.Name;
+                dto.UnreadCount = (int)(x.MaxSequenceId - x.c.LastReadSequenceId ?? 0);
+                dto.LastSequenceId = x.MaxSequenceId;
+                dto.LastMessage = x.LastMessage;
                 return dto;
             });