-- A seat keeps its former names, so a rename breaks nothing (novox/hq ADR 0122).
--
-- Phase 1 made the seat set data, but a rename still broke every reference to the old name — a
-- manifest's claim, a held record, the git-seat lookup — because they name the seat and the name
-- had changed. This is the stable identity ADR 0122 asked for, realised the simple way: a seat's
-- canonical name changes, and its old name becomes an alias that resolves to it forever. Nothing
-- downstream has to change — a manifest goes on claiming the old name, the build machine goes on
-- validating it — and a rename is one operation: set the new name, remember the old.
create table seat_alias (
  alias text primary key,       -- a former name of a seat
  seat  text not null           -- the seat's current canonical name it resolves to
);