fix(typecheck): infer Ref<T> kind as arity-1 ctor (#135 slice 10)

effects.affine externs (make_ref/get/set) use Ref<T>, an undeclared
opaque type constructor from the `state` effect. infer_kind hardcodes
known opaque ctors (Array/Option/List/Vec/Cmd arity-1, Result arity-2)
and falls back to KType for the rest, so TApp(Ref,[T]) hit
check_kind_app's 'Too many arguments for kind'. Ref is the direct
analogue of Cmd (Stage-11 opaque effect ctor) — add it to the arity-1
list. effects.affine now compiles resolve->typecheck; 12/19 stdlib
green, zero regression.

Refs #128

Author: hyperpolymath

lib/typecheck.ml

@@ -311,7 +311,7 @@ let rec infer_kind (ctx : context) (ty : ty) : kind result =
     end
   | TCon name ->
     begin match name with
-      | "Array" | "Option" | "List" | "Vec" | "Cmd" -> Ok (KArrow (KType, KType))
+      | "Array" | "Option" | "List" | "Vec" | "Cmd" | "Ref" -> Ok (KArrow (KType, KType))
       | "Result" -> Ok (KArrow (KType, KArrow (KType, KType)))
       | _ -> Ok KType
     end