ocaml: numeric tower — Integer/Number distinction + float contagion
Add `Integer of int` to sx_types.ml alongside `Number of float`. Parser
produces Integer for whole-number literals. Arithmetic primitives apply
float contagion (int op int → Integer, int op float → Number). Division
always returns Number. Rounding (floor/truncate/round) returns Integer.
Predicates: integer?, float?, exact?, inexact?, exact->inexact,
inexact->exact. run_tests.ml updated for json_of_value, value_of_json,
identical?, random-int mock, DOM accessors, and parser pattern matches.
New spec/tests/test-numeric-tower.sx — 92 tests, all pass (394 unchanged).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
giles
c70bbdeb36