A controller whose defaults carry the new name seeds it before the migration runs, and the first
form renamed into a duplicate key; the control node's prepare failed on every attempt (2026-09-30).
If the new row exists, the old row's holding moves to it and the old row goes; otherwise it is
renamed. The old name becomes an alias either way.
ADR 0121 decided it and deferred it as a delivering-seat migration; ADR 0122's aliases made it one
update and one alias (migration 0048). The former name resolves to it forever (novox/hq ADR 0156,
issue 123).
jschoubben