Soul's sixth pass (N1): every CallScope destructor wakes every waiter, so
without the predicate a poll leaves whenever another host thread makes any
call. Every scenario had a single-threaded host, and dropping the predicate
survived the whole matrix on both targets.
`pollbusy` is a public-API scenario and needs no development seam. A second
host thread calls `cultmesh_quic_last_error` every 20 ms for twice the
poll's timeout while an idle `poll(1000)` waits. It checks the timing first.
It then checks the other thread's call count, so a poll that passed without
ever being woken reads as the fixture failing.
Three harness entries:
- revert: no predicate, `woken` taken from `cv_status`;
- loosening: the wait reads what woke it and does not wait again;
- loosening: a hand-written loop that restarts the whole timeout on every
wake. Its lateness is a function of the input.
Each was compiled in and run through every scenario on both targets:
- revert and read-what-woke: `pollbusy` returns at 0 ms;
- re-arm: `pollbusy` returns at about 3000 ms.
The earlier scenarios all stay green under all three. The harness kills all
three on both targets.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>