fix: 删除重复的Upload模型文件，保留UploadModels.cs统一定义

- 删除 GetPresignedUrlRequest.cs (已在UploadModels.cs中定义)
- 删除 PresignedUrlResponse.cs (已在UploadModels.cs中定义)
- 删除 UploadResponse.cs (已在UploadModels.cs中定义)
- 删除 UploadResult.cs (已在UploadModels.cs中定义)

解决重复类定义导致的编译错误，统一使用UploadModels.cs管理所有Upload相关模型

server/HoneyBox/src/HoneyBox.Admin.Business/Models/Upload/GetPresignedUrlRequest.cs

@@ -1,9 +0,0 @@
-namespace HoneyBox.Admin.Business.Models.Upload;
-
-public class GetPresignedUrlRequest
-{
-    public string FileName { get; set; } = string.Empty;
-    public string ContentType { get; set; } = string.Empty;
-    public int ExpiresInSeconds { get; set; } = 600;
-    public long FileSize { get; set; }
-}

server/HoneyBox/src/HoneyBox.Admin.Business/Models/Upload/PresignedUrlResponse.cs

@@ -1,14 +0,0 @@
-namespace HoneyBox.Admin.Business.Models.Upload;
-
-public class PresignedUrlResponse
-{
-    public bool Success { get; set; }
-    public string? UploadUrl { get; set; }
-    public string? AccessUrl { get; set; }
-    public string? ErrorMessage { get; set; }
-    public DateTime ExpiresAt { get; set; }
-    public string? FileUrl { get; set; }
-    public string? ObjectKey { get; set; }
-    public int ExpiresIn { get; set; }
-    public string? StorageType { get; set; }
-}

server/HoneyBox/src/HoneyBox.Admin.Business/Models/Upload/UploadResponse.cs

@@ -1,10 +0,0 @@
-namespace HoneyBox.Admin.Business.Models.Upload;
-
-public class UploadResponse
-{
-    public bool Success { get; set; }
-    public string? Url { get; set; }
-    public string? FileName { get; set; }
-    public long FileSize { get; set; }
-    public string? ErrorMessage { get; set; }
-}

server/HoneyBox/src/HoneyBox.Admin.Business/Models/Upload/UploadResult.cs

@@ -1,18 +0,0 @@
-namespace HoneyBox.Admin.Business.Models.Upload;
-
-public class UploadResult
-{
-    public bool Success { get; set; }
-    public string? Url { get; set; }
-    public string? ErrorMessage { get; set; }
-
-    public static UploadResult Ok(string url)
-    {
-        return new UploadResult { Success = true, Url = url };
-    }
-
-    public static UploadResult Fail(string errorMessage)
-    {
-        return new UploadResult { Success = false, ErrorMessage = errorMessage };
-    }
-}