fix: 修复文件列表为空时的返回值处理并添加图像处理相关依赖

Core/FileManager.cs

@@ -109,6 +109,10 @@ namespace MegghysAPI.Core
                     .WithIncludeUserMetadata(includeUserMetadata));
 
                 var fileList = new List<Minio.DataModel.Item>();
+                if(fileList.Count == 0)
+                {
+                    return [];
+                }
                 await foreach (var item in result)
                 {
                     fileList.Add(item);