Replace the one-shot minio-createbuckets service (which required a
manual 'abra app restart minio-createbuckets' that appeared to hang)
with a minio-initialize.sh config, ported from lasuite-docs. The minio
service entrypoint runs it in the background before starting minio; it
waits for minio to be ready and idempotently creates the
drive-media-storage bucket with versioning. Manual trigger:
'abra app cmd minio minio_initialize'.
