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/download.py

@@ -0,0 +1,198 @@
+from enum import StrEnum
+from typing import TYPE_CHECKING, Annotated
+from uuid import UUID
+
+from sqlmodel import Field, Relationship, UniqueConstraint, Index
+
+from .base import SQLModelBase
+from .mixin import UUIDTableBaseMixin, TableBaseMixin
+
+if TYPE_CHECKING:
+    from .user import User
+    from .task import Task
+    from .node import Node
+
+class DownloadStatus(StrEnum):
+    """下载状态枚举"""
+    PREPARING = "preparing"
+    """准备中"""
+    RUNNING = "running"
+    """进行中"""
+    COMPLETED = "completed"
+    """已完成"""
+    ERROR = "error"
+    """错误"""
+
+
+class DownloadType(StrEnum):
+    """下载类型枚举"""
+    # [TODO] 补充具体下载类型
+    pass
+
+
+# ==================== Aria2 信息模型 ====================
+
+class DownloadAria2InfoBase(SQLModelBase):
+    """Aria2下载信息基础模型"""
+
+    info_hash: Annotated[str | None, Field(max_length=40)] = None
+    """InfoHash（BT种子）"""
+
+    piece_length: int = 0
+    """分片大小"""
+
+    num_pieces: int = 0
+    """分片数量"""
+
+    num_seeders: int = 0
+    """做种人数"""
+
+    connections: int = 0
+    """连接数"""
+
+    upload_speed: int = 0
+    """上传速度（bytes/s）"""
+
+    upload_length: int = 0
+    """已上传大小（字节）"""
+
+    error_code: str | None = None
+    """错误代码"""
+
+    error_message: str | None = None
+    """错误信息"""
+
+
+class DownloadAria2Info(DownloadAria2InfoBase, SQLModelBase, table=True):
+    """Aria2下载信息模型（与Download一对一关联）"""
+
+    download_id: UUID = Field(
+        foreign_key="download.id",
+        primary_key=True,
+        ondelete="CASCADE"
+    )
+    """关联的下载任务UUID"""
+
+    # 反向关系
+    download: "Download" = Relationship(back_populates="aria2_info")
+    """关联的下载任务"""
+
+
+class DownloadAria2File(SQLModelBase, TableBaseMixin):
+    """Aria2下载文件列表（与Download一对多关联）"""
+
+    download_id: UUID = Field(
+        foreign_key="download.id",
+        index=True,
+        ondelete="CASCADE"
+    )
+    """关联的下载任务UUID"""
+
+    file_index: int = Field(ge=1)
+    """文件索引（从1开始）"""
+
+    path: str
+    """文件路径"""
+
+    length: int = 0
+    """文件大小（字节）"""
+
+    completed_length: int = 0
+    """已完成大小（字节）"""
+
+    is_selected: bool = True
+    """是否选中下载"""
+
+    # 反向关系
+    download: "Download" = Relationship(back_populates="aria2_files")
+    """关联的下载任务"""
+
+
+# ==================== 主模型 ====================
+
+class DownloadBase(SQLModelBase):
+    pass
+
+class Download(DownloadBase, UUIDTableBaseMixin):
+    """离线下载任务模型"""
+
+    __table_args__ = (
+        UniqueConstraint("node_id", "g_id", name="uq_download_node_gid"),
+        Index("ix_download_user_status", "user_id", "status"),
+    )
+
+    status: DownloadStatus = Field(default=DownloadStatus.PREPARING, index=True)
+    """下载状态"""
+
+    type: int = Field(default=0)
+    """任务类型 [TODO] 待定义枚举"""
+
+    source: str
+    """来源URL或标识"""
+
+    total_size: int = Field(default=0)
+    """总大小（字节）"""
+
+    downloaded_size: int = Field(default=0)
+    """已下载大小（字节）"""
+
+    g_id: str | None = Field(default=None, index=True)
+    """Aria2 GID"""
+
+    speed: int = Field(default=0)
+    """下载速度（bytes/s）"""
+
+    parent: str | None = Field(default=None, max_length=255)
+    """父任务标识"""
+
+    error: str | None = Field(default=None)
+    """错误信息"""
+
+    dst: str
+    """目标存储路径"""
+
+    # 外键
+    user_id: UUID = Field(
+        foreign_key="user.id",
+        index=True,
+        ondelete="CASCADE"
+    )
+    """所属用户UUID"""
+
+    task_id: int | None = Field(
+        default=None,
+        foreign_key="task.id",
+        index=True,
+        ondelete="SET NULL"
+    )
+    """关联的任务ID"""
+
+    node_id: int = Field(
+        foreign_key="node.id",
+        index=True,
+        ondelete="RESTRICT"
+    )
+    """执行下载的节点ID"""
+
+    # 关系
+    aria2_info: DownloadAria2Info | None = Relationship(
+        back_populates="download",
+        sa_relationship_kwargs={"uselist": False, "cascade": "all, delete-orphan"},
+    )
+    """Aria2下载信息"""
+
+    aria2_files: list[DownloadAria2File] = Relationship(
+        back_populates="download",
+        sa_relationship_kwargs={"cascade": "all, delete-orphan"}
+    )
+    """Aria2文件列表"""
+
+    user: "User" = Relationship(back_populates="downloads")
+    """所属用户"""
+
+    task: "Task" = Relationship(back_populates="downloads")
+    """关联的任务"""
+
+    node: "Node" = Relationship(back_populates="downloads")
+    """执行下载的节点"""
+