fix: align backend APIs and upload flow

MessageService.Infrastructure/Reposities/MessageReposity.cs

@@ -26,30 +26,32 @@ namespace MessageService.Infrastructure.Reposities
         public async Task<(IEnumerable<Message> messages, bool hasMore)> GetAsync(string streamKey, long? cusor, int direction, int limit)
         {
             var query = db.Messages.Where(x => x.StreamKey == streamKey);
-            List<Message> messages = [];
+            List<Message> fetched;
             if (direction == 0) // Before: 找比锚点小的，按倒序排
             {
                 if (cusor.HasValue)
                     query = query.Where(m => m.SequenceId < cusor.Value);
 
-                var list = await query
+                fetched = await query
                     .OrderByDescending(m => m.SequenceId) // 最新消息在最前
                     .Take(limit + 1)
                     .ToListAsync();
-
-                messages = [.. list.OrderBy(s => s.SequenceId)];
             }
             else
             {
                 if (cusor is null)
-                    return (messages, false);
+                    return (Array.Empty<Message>(), false);
 
-                messages = await query.OrderBy(o => o.SequenceId)
+                fetched = await query
+                    .Where(m => m.SequenceId > cusor.Value)
+                    .OrderBy(o => o.SequenceId)
                     .Take(limit + 1)
                     .ToListAsync();
             }
 
-            return (messages, messages.Count > limit);
+            var hasMore = fetched.Count > limit;
+            var messages = fetched.Take(limit).OrderBy(s => s.SequenceId).ToList();
+            return (messages, hasMore);
         }
     }
 }