Amazon Redshift control-plane implementation for FakeCloud.
Redshift's control plane is pure state CRUD: clusters, snapshots,
parameter/subnet/security groups, HSM objects, event subscriptions,
scheduled actions, usage limits, endpoint access, datashares, and so on.
Unlike RDS/ElastiCache there is no data plane to run (SQL access is a
separate service, redshift-data), so nothing here spawns containers —
every resource is modelled as real persisted state with real CRUD,
validation, pagination, and AWS-faithful error codes.