- No longer written with a seamless transition in mind. It's probably
possible, but untested, and I believe most deployments do a hard cutover
anyhow. Since this is just Studio, logging everyone out is probably
acceptable.
- Remove decline-migration section since we don't believe anyone is likely
to need this (and we're deprecating it anyhow.)
- Remove `/login/` config changes, since those have already been performed
in the common env and were only required for seamless migration. Remove
cleanup for same reason.
- Give hint about domain-changing
ref ARCHBOM-1890
e97070808f