feat: finalize core modules and gateway

src/Application/TakeoutSaaS.Application/Storage/Contracts/DirectUploadResponse.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+
+namespace TakeoutSaaS.Application.Storage.Contracts;
+
+/// <summary>
+/// 直传凭证响应模型。
+/// </summary>
+public sealed class DirectUploadResponse
+{
+    /// <summary>
+    /// 预签名上传地址。
+    /// </summary>
+    public string UploadUrl { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 表单直传所需字段（PUT 直传为空）。
+    /// </summary>
+    public IReadOnlyDictionary<string, string> FormFields { get; set; } = new Dictionary<string, string>();
+
+    /// <summary>
+    /// 预签名过期时间。
+    /// </summary>
+    public DateTimeOffset ExpiresAt { get; set; }
+
+    /// <summary>
+    /// 对象键。
+    /// </summary>
+    public string ObjectKey { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 直传完成后的访问链接（包含签名）。
+    /// </summary>
+    public string? DownloadUrl { get; set; }
+}