Lakebase V1 transaction auth retry uses original client for transaction boundaries

[fallintoplace]

Summary

LakebaseV1Connector.transaction() rotates credentials on 28P01, opens a retry client, and passes that retry client to the transaction callback. The retry path still executes BEGIN and COMMIT on the original client, which has already been released.

Impact

The callback work and transaction boundaries can run on different PostgreSQL clients. In practice the retry path may fail immediately because the original client was released, or it may leave the retry callback work outside the intended transaction.

Expected

After credential rotation, BEGIN, callback work, COMMIT, and rollback handling should all use the retry client.

Repro Pointer

See packages/appkit/src/connectors/lakebase-v1/client.ts in the auth retry branch of transaction().