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.

tests/test_database.py

@@ -3,14 +3,14 @@ import pytest
 @pytest.mark.asyncio
 async def test_initialize_db():
     """测试创建数据库结构"""
-    from models import database
+    from sqlmodels import database
     
     await database.init_db(url='sqlite:///:memory:')
 
 @pytest.fixture
 async def db_session():
     """测试获取数据库连接Session"""
-    from models import database
+    from sqlmodels import database
     
     await database.init_db(url='sqlite:///:memory:')
     
@@ -20,8 +20,8 @@ async def db_session():
 @pytest.mark.asyncio
 async def test_migration():
     """测试数据库创建并初始化配置"""
-    from models import migration
-    from models import database
+    from sqlmodels import migration
+    from sqlmodels import database
     
     await database.init_db(url='sqlite:///:memory:')