refactor: Reorganize datamate-python (#34)

refactor: Reorganize datamate-python (previously label-studio-adapter) into a DDD style structure.

runtime/datamate-python/app/db/session.py

@@ -0,0 +1,38 @@
+from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine, async_sessionmaker
+from sqlalchemy.orm import declarative_base
+from app.core.config import settings
+from app.core.logging import get_logger
+from typing import AsyncGenerator
+
+logger = get_logger(__name__)
+
+# 获取数据库配置信息
+db_info = settings.get_database_info()
+logger.info(f"使用数据库: {db_info['type']} || 连接URL: {db_info['url']}")
+
+# 创建数据库引擎
+engine = create_async_engine(
+    settings.computed_database_url,
+    echo=False,  # 关闭SQL调试日志以减少输出
+    future=True,
+    # SQLite特殊配置
+    connect_args={"check_same_thread": False} if "sqlite" in settings.computed_database_url else {}
+)
+
+# 创建会话工厂
+AsyncSessionLocal = async_sessionmaker(
+    engine, 
+    class_=AsyncSession, 
+    expire_on_commit=False
+)
+
+# 创建基础模型类
+Base = declarative_base()
+async def get_db() -> AsyncGenerator[AsyncSession, None]:
+    """获取数据库会话"""
+    async with AsyncSessionLocal() as session:
+        try:
+            yield session
+        finally:
+            await session.close()
+