Found doing the per-backend provider e2e: redis and postgres accept the mesh's `as`
(mesh_<node>_<module>) verbatim, but minio's S3 access key is capped at 20 chars and
`as` is 22, so the provisioner cannot create the service account. `as` is doing two
jobs — a stable identity the two ends agree on, and a literal identifier a backend
must accept — and those are not always the same string.
Claude-Session: https://claude.ai/code/session_01LrgweAeERJYBg88c5cKDzF
