Functors were already wired through ocaml-make-functor in eval.sx
(curried host closure consuming module dicts) but had no explicit
tests for the user-defined Ord application path. This commit adds
three smoke tests that confirm:
module IntOrd = struct let compare a b = a - b end
module S = Set.Make (IntOrd)
S.elements (fold-add [5;1;3;1;5]) sums to 9 (dedupe + sort)
S.mem 2 (S.add 1 (S.add 2 (S.add 3 S.empty))) = true
M.cardinal (M.add 1 'a' (M.add 2 'b' M.empty)) = 2
The Ord parameter is properly threaded through the functor body —
elements are sorted in compare order and dedupe works.