ino is membero with the constraint-store-friendly argument order
(`(ino x dom)` reads as "x in dom"). all-distincto checks pairwise
distinctness via nafc + membero on the recursive tail. These two are
enough to express the enumerate-then-filter style of finite-domain
solving:
(fresh (a b c)
(ino a (list 1 2 3)) (ino b (list 1 2 3)) (ino c (list 1 2 3))
(all-distincto (list a b c)))
enumerates all 6 distinct triples from {1, 2, 3}. Full CLP(FD) with
arc-consistency, fd-plus, etc. remains pending under Phase 6 proper.
9 new tests, 237/237 cumulative.