With the pending_cek snapshot fix, _driveAsync no longer causes
duplicate resume chains. Needed for event-triggered suspensions
(btn.click → handler → perform) where the suspension propagates
through addEventListener, invisible to the outer eval.
Sandbox bytecode test: 6/6 io-sleep suspensions confirmed.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>