feat: add models for physical files, policies, and user management

- Implement PhysicalFile model to manage physical file references and reference counting.
- Create Policy model with associated options and group links for storage policies.
- Introduce Redeem and Report models for handling redeem codes and reports.
- Add Settings model for site configuration and user settings management.
- Develop Share model for sharing objects with unique codes and associated metadata.
- Implement SourceLink model for managing download links associated with objects.
- Create StoragePack model for managing user storage packages.
- Add Tag model for user-defined tags with manual and automatic types.
- Implement Task model for managing background tasks with status tracking.
- Develop User model with comprehensive user management features including authentication.
- Introduce UserAuthn model for managing WebAuthn credentials.
- Create WebDAV model for managing WebDAV accounts associated with users.

sqlmodels/mixin/info_response.py

@@ -0,0 +1,46 @@
+"""
+InfoResponse DTO Mixin模块
+
+提供用于InfoResponse类型DTO的Mixin，统一定义id/created_at/updated_at字段。
+
+设计说明：
+- 这些Mixin用于**响应DTO**，不是数据库表
+- 从数据库返回时这些字段永远不为空，所以定义为必填字段
+- TableBase中的id=None和default_factory=now是正确的（入库前为None，数据库生成）
+- 这些Mixin让DTO明确表示"返回给客户端时这些字段必定有值"
+"""
+from datetime import datetime
+from uuid import UUID
+
+from sqlmodels.base import SQLModelBase
+
+
+class IntIdInfoMixin(SQLModelBase):
+    """整数ID响应mixin - 用于InfoResponse DTO"""
+    id: int
+    """记录ID"""
+
+
+class UUIDIdInfoMixin(SQLModelBase):
+    """UUID ID响应mixin - 用于InfoResponse DTO"""
+    id: UUID
+    """记录ID"""
+
+
+class DatetimeInfoMixin(SQLModelBase):
+    """时间戳响应mixin - 用于InfoResponse DTO"""
+    created_at: datetime
+    """创建时间"""
+
+    updated_at: datetime
+    """更新时间"""
+
+
+class IntIdDatetimeInfoMixin(IntIdInfoMixin, DatetimeInfoMixin):
+    """整数ID + 时间戳响应mixin"""
+    pass
+
+
+class UUIDIdDatetimeInfoMixin(UUIDIdInfoMixin, DatetimeInfoMixin):
+    """UUID ID + 时间戳响应mixin"""
+    pass