Lifespan (one-time setup/teardown)

For expensive setup like database creation:

async def db_lifespan():
    await create_database()
    yield
    await drop_database()

@checkpointer_test(name="PostgresSaver", lifespan=db_lifespan)
async def pg_checkpointer():
    async with PostgresSaver.from_conn_string(CONN_STRING) as saver:
        yield saver