oceanbase_py's has_table() -- called by create_all()'s default
checkfirst=True before creating each table -- passes a raw string
straight to Connection.execute(), which SQLAlchemy 2.0 rejects outright
(ObjectNotExecutableError, confirmed on real CI). Added an optional
checkfirst override to the shared _pagination.py helper and used it here;
safe to skip the existence check since each test gets a genuinely fresh
container.