Workers set PR_SET_PDEATHSIG(SIGKILL) against their EngineCore parent with a getppid race check. Start methods other than fork/spawn are refused before any worker is created. Subprocess tests cover fork, spawn, graceful SIGTERM and the refusal. Co-Authored-By: Hinata <hinata@idihore.id> Signed-off-by: MOVZX <movzx@yahoo.com>