feat: 支持S3预签名上传

apps/base/schemas.py

@@ -1,4 +1,5 @@
 from pydantic import BaseModel
+from typing import Optional
 
 
 class SelectFileModel(BaseModel):
@@ -15,3 +16,21 @@ class InitChunkUploadModel(BaseModel):
 class CompleteUploadModel(BaseModel):
     expire_value: int
     expire_style: str
+
+
+# 预签名上传相关模型
+class PresignUploadInitRequest(BaseModel):
+    """预签名上传初始化请求"""
+    file_name: str
+    file_size: int
+    expire_value: int = 1
+    expire_style: str = "day"
+
+
+class PresignUploadInitResponse(BaseModel):
+    """预签名上传初始化响应"""
+    upload_id: str
+    upload_url: str
+    mode: str  # "direct" 或 "proxy"
+    save_path: str
+    expires_in: int  # URL过期时间（秒）