Static + binary-level regression test (free, <1s): asserts the flags are
wired, the plan-tune read is time-bounded (no bare blocking read), explicit
yes/no decisions short-circuit before the prompt, and gstack-config knows the
plan_tune_hooks key.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Garry Tan