SafeRules

Every rule in All whose
Growth is known not to expand and whose
Soundness is at least SoundUnderAssumptions -- the real pattern-tree classification (Task 4), not the public registry's
string-length proxy, and a per-rule Soundness check the previous,
public-surface-sourced version of this field had no way to make (it filtered by
Growth alone). Computed once: the registry does not change while the process runs.