JetStreamAsks.WatchAsk opens the watch as a kept call and takes a closed watch up after the last revision heard; the first
fault arms a key of the state bounds with its own time to live (StepsBoundKey), whose end while the read is unanswered raises
call-unanswered about the ask, and the answer ends it.
Builds: design 47 G §568, A-77
Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h