lib/maude/conditional.sx — condition-aware reducer. ceq fires only when
its guard holds: equational guards (l=r reduce to same normal form) and
boolean guards (term reduces to true), evaluated by recursing through the
same reducer. Verified on gcd, insertion sort, max, even.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
