Switch active-app presents to drawable acquisition after 500 ms of display-link
silence, then retry with exponential backoff capped at 60 seconds. Preserve the
requested pacing mode, synchronize rescue state, and prevent focus timestamp
underflow from bypassing the foreground grace period.
Add CPU regression coverage in CI, a real Metal layer ownership check, and the
mechanism reference with upstream provenance and validation limits.
Validated: 43 CPU rescue checks; 47 checks with real Metal drawable acquisition;
34 present/crop and 10 pacing checks; Wonder Mac host build; all 133 iOS source
compile checks; documentation tests. Windowed gameplay recovery and iPhone
validation remain outstanding.
Co-authored-by: Aleksandr Svidchenkov <a.svidchenkov@gmail.com>
