Schedule test drives _pairs[i].explode/coalesce and patches _advance(index, buffer) for the stale L1->L2 feed mutant; remap rejection test patches _boundary_hosts entries and hierarchy.pairs instead of the read-only views; the GPU launch-failure test patches _pairs[0].explode. Assertions unchanged. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>