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/webdav.py

@@ -0,0 +1,33 @@
+
+from typing import TYPE_CHECKING
+from uuid import UUID
+
+from sqlmodel import Field, Relationship, UniqueConstraint
+
+from .base import SQLModelBase
+from .mixin import TableBaseMixin
+
+if TYPE_CHECKING:
+    from .user import User
+
+class WebDAV(SQLModelBase, TableBaseMixin):
+    """WebDAV账户模型"""
+
+    __table_args__ = (UniqueConstraint("name", "user_id", name="uq_webdav_name_user"),)
+
+    name: str = Field(max_length=255, description="WebDAV账户名")
+    password: str = Field(max_length=255, description="WebDAV密码")
+    root: str = Field(default="/", sa_column_kwargs={"server_default": "'/'"}, description="根目录路径")
+    readonly: bool = Field(default=False, description="是否只读")
+    use_proxy: bool = Field(default=False, description="是否使用代理下载")
+    
+    # 外键
+    user_id: UUID = Field(
+        foreign_key="user.id",
+        index=True,
+        ondelete="CASCADE"
+    )
+    """所属用户UUID"""
+    
+    # 关系
+    user: "User" = Relationship(back_populates="webdavs")