(/ int int) returns float per spec/host parity (was leaking exact rationals into arithmetic + CSS, e.g. tw-opacity 1/20); rational operand still yields exact rational. number?/exact? recognise Rational. test-rationals typo fix. OCaml conformance 4834->4863, rational/numeric-tower/arithmetic/tw-opacity green. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>