Acceptance bar hit (40 runtime, 497 total). Tests: timer ready,
select-with-timeout, fan-in (3 producers), worker queue, pipeline,
fan-out-then-fan-in, select source-order, fallback case, default,
producer-consumer, two-stage pipeline, channel-counter, after+default,
tick-collector.
Shape chiselled: timer collapses "after duration" into
"channel ready immediately" — select needs only ready? from each
case. Real time is when the flip happens, not what the protocol is.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>