The gs:// backend was already opt-in behind `-tags gcs`, but go mod tidy sees
tagged-out files, so cloud.google.com/go/storage and its grpc chain stayed in
go.mod for a backend no build enabled. Both the real file and its stub are gone
and NewArchive dispatches s3:// alone — every Hanzo and Lux deploy ships
MinIO-protocol S3 (hanzoai/s3), so gs:// was never reachable in practice.