matche-pattern->expr now treats keyword patterns as literals that emit
themselves bare, rather than wrapping in (quote ...). SX keywords
self-evaluate to their string name; quoting them flips them to a
keyword type that does not unify with the bare-keyword usage at the
target site. This was visible only as a test failure on the diffo
clauses below — tightened the pattern rules.
tests/classics.sx exercises three end-to-end miniKanren programs:
- 3-friend / 3-pet permutation puzzle
- grandparent inference over a fact list (membero + fresh)
- symbolic differentiation dispatched by matche on
:x / (:+ a b) / (:* a b)
228/228 cumulative.