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/policy.py

@@ -0,0 +1,187 @@
+from typing import TYPE_CHECKING
+from uuid import UUID
+
+from enum import StrEnum
+from sqlmodel import Field, Relationship, text
+
+from .base import SQLModelBase
+from .mixin import UUIDTableBaseMixin
+
+if TYPE_CHECKING:
+    from .object import Object
+    from .group import Group
+
+
+class GroupPolicyLink(SQLModelBase, table=True):
+    """用户组与存储策略的多对多关联表"""
+
+    group_id: UUID = Field(
+        foreign_key="group.id",
+        primary_key=True,
+        ondelete="CASCADE"
+    )
+    """用户组UUID"""
+
+    policy_id: UUID = Field(
+        foreign_key="policy.id",
+        primary_key=True,
+        ondelete="CASCADE"
+    )
+    """存储策略UUID"""
+
+
+class PolicyType(StrEnum):
+    LOCAL = "local"
+    S3 = "s3"
+
+
+class PolicyBase(SQLModelBase):
+    """存储策略基础字段，供 DTO 和数据库模型共享"""
+
+    name: str = Field(max_length=255)
+    """策略名称"""
+
+    type: PolicyType
+    """存储策略类型"""
+
+    server: str | None = Field(default=None, max_length=255)
+    """服务器地址（本地策略为绝对路径）"""
+
+    bucket_name: str | None = Field(default=None, max_length=255)
+    """存储桶名称"""
+
+    is_private: bool = True
+    """是否为私有空间"""
+
+    base_url: str | None = Field(default=None, max_length=255)
+    """访问文件的基础URL"""
+
+    access_key: str | None = None
+    """Access Key"""
+
+    secret_key: str | None = None
+    """Secret Key"""
+
+    max_size: int = Field(default=0, ge=0)
+    """允许上传的最大文件尺寸（字节）"""
+
+    auto_rename: bool = False
+    """是否自动重命名"""
+
+    dir_name_rule: str | None = Field(default=None, max_length=255)
+    """目录命名规则"""
+
+    file_name_rule: str | None = Field(default=None, max_length=255)
+    """文件命名规则"""
+
+    is_origin_link_enable: bool = False
+    """是否开启源链接访问"""
+
+
+# ==================== DTO 模型 ====================
+
+
+class PolicySummary(SQLModelBase):
+    """策略摘要，用于列表展示"""
+
+    id: UUID
+    """策略UUID"""
+
+    name: str
+    """策略名称"""
+
+    type: PolicyType
+    """策略类型"""
+
+    server: str | None
+    """服务器地址"""
+
+    max_size: int
+    """最大文件尺寸"""
+
+    is_private: bool
+    """是否私有"""
+
+
+# ==================== 数据库模型 ====================
+
+
+class PolicyOptionsBase(SQLModelBase):
+    """存储策略选项的基础模型"""
+
+    token: str | None = Field(default=None)
+    """访问令牌"""
+
+    file_type: str | None = Field(default=None)
+    """允许的文件类型"""
+
+    mimetype: str | None = Field(default=None, max_length=127)
+    """MIME类型"""
+
+    od_redirect: str | None = Field(default=None, max_length=255)
+    """OneDrive重定向地址"""
+
+    chunk_size: int = Field(default=52428800, sa_column_kwargs={"server_default": "52428800"})
+    """分片上传大小（字节），默认50MB"""
+
+    s3_path_style: bool = Field(default=False, sa_column_kwargs={"server_default": text("false")})
+    """是否使用S3路径风格"""
+
+
+class PolicyOptions(PolicyOptionsBase, UUIDTableBaseMixin):
+    """存储策略选项模型（与Policy一对一关联）"""
+
+    policy_id: UUID = Field(
+        foreign_key="policy.id",
+        unique=True,
+        ondelete="CASCADE"
+    )
+    """关联的策略UUID"""
+
+    # 反向关系
+    policy: "Policy" = Relationship(back_populates="options")
+    """关联的策略"""
+
+
+class Policy(PolicyBase, UUIDTableBaseMixin):
+    """存储策略模型"""
+
+    # 覆盖基类字段以添加数据库专有配置
+    name: str = Field(max_length=255, unique=True)
+    """策略名称"""
+
+    is_private: bool = Field(default=True, sa_column_kwargs={"server_default": text("true")})
+    """是否为私有空间"""
+
+    max_size: int = Field(default=0, sa_column_kwargs={"server_default": "0"})
+    """允许上传的最大文件尺寸（字节）"""
+
+    auto_rename: bool = Field(default=False, sa_column_kwargs={"server_default": text("false")})
+    """是否自动重命名"""
+
+    is_origin_link_enable: bool = Field(default=False, sa_column_kwargs={"server_default": text("false")})
+    """是否开启源链接访问"""
+
+    # 一对一关系：策略选项
+    options: PolicyOptions | None = Relationship(
+        back_populates="policy",
+        sa_relationship_kwargs={"uselist": False, "cascade": "all, delete-orphan"},
+    )
+    """策略的扩展选项"""
+
+    # 关系
+    objects: list["Object"] = Relationship(back_populates="policy")
+    """策略下的所有对象"""
+
+    # 多对多关系：策略可以被多个用户组使用
+    groups: list["Group"] = Relationship(
+        back_populates="policies",
+        link_model=GroupPolicyLink,
+    )
+    
+    @staticmethod
+    async def create(
+        policy: 'Policy | None' = None,
+        **kwargs
+    ):
+        pass