The 1-arg map/filter/remove/take/drop/take-while/drop-while/mapcat now return a
transducer (fn [rf] rf'), and into gets a 3-arg (into to xform from). This was
the 'cdr () is not a pair' / 'incorrect number of arguments' crash bucket: the
emitter lowers (map f) and 3-arg into at an arity the native-op gate rejects, so
they fall to the value-position path and hit the bare jolt-map/jolt-into
procedure at the wrong arity. The fix is RT-side — case-lambda those procedures
plus jolt-into.
td-* factories ported from the seed (core_coll.janet); a reduced step stops the
fold via reduce-seq's existing short-circuit (inc 3n). transduce/comp/completing
are overlay and compose over these unchanged.
Parity 1467 -> 1493/2497, 0 new divergences. emit-test 278/278.
cbb0f2ab4a