The teller hears pipeline-ended, tells each end that carries widens through the seat operator-channel's notify with every-channel,
one line per entry, and keeps the last commit said per module and watched branch in its state widens-said (read by
teller_widens_said); registration-changed drops the branches no longer watched.
Builds: design 47 G §71, §335, §514, §522
Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h