Main reverted G's half merge (#189, reverted by 8afc3eb in #191) and then took the reader release's S1-S5, which
copied G's code. G's form holds where they differ (process_bus.go, seats.go, state.go and their tests); the
release's kept names stay so main's callers keep building: SeatViewPrefix beside SeatReadPrefix, and QueueInvoke's
empty strings on not-ok (with its test TestQueueInvoke). The tree differs from G's head f30dee54 only by those and
the release's two tests (objects cap option, seat states and stream kinds).
Builds: design 47 G (the milestone's sdk part, as at f30dee54)
Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h
jschoubben
5fa64be894