refactor: 完成数据库重构 - 批量更新导入路径

- 更新35个文件的导入路径 (共65处修改)
- sqlalchemy_models  core.models (模型类)
- sqlalchemy_database_api  compatibility (兼容函数)
- database.database  core (初始化/关闭函数)
- 添加自动化导入更新工具 (scripts/update_database_imports.py)
- 所有兼容性层测试通过 (26/26)
- 数据库核心功能测试通过 (18/21)

src/plugin_system/core/permission_manager.py

@@ -10,7 +10,7 @@ from sqlalchemy import delete, select
 from sqlalchemy.exc import IntegrityError, SQLAlchemyError
 from sqlalchemy.ext.asyncio import async_sessionmaker
 
-from src.common.database.sqlalchemy_models import PermissionNodes, UserPermissions, get_engine
+from src.common.database.core.models import PermissionNodes, UserPermissions, get_engine
 from src.common.logger import get_logger
 from src.config.config import global_config
 from src.plugin_system.apis.permission_api import IPermissionManager, PermissionNode, UserInfo