The reviewer's standing issue: the child inherits the host's SIGXCPU
disposition and signal mask — if the host ignores or blocks SIGXCPU, the soft
RLIMIT_CPU fires but cannot stop the child, and the hard limit's SIGKILL then
classifies a definite CPU overrun as worker-exit instead of a timeout. The
bootstrap now resets SIGXCPU to SIG_DFL and unblocks it before any model code
runs (the settle-time enforcer already restores SIG_DFL for a program that
traps or masks the signal mid-run; this closes the inherited-state gap). The
zh README's outer wire section also gains the truncation-exception sentence to
match the en side.
7b9db83f86