Total order over DXN values. Cross-kind comparisons fall back to
KIND_RANK (this library's own implementation-defined choice, see
module doc); same-kind comparisons use each kind's natural order.
Structural equality between two DXN values, recursing into every
collection/wrapper shape. Two NaN floats are equal (DXN treats
NaN as one specific scalar value, not "incomparable" the way IEEE
754 === does).
Identifies the DXN "kind" of a value for cross-type ranking and
same-kind dispatch. Native JS shapes are recognized directly;
DXN* wrapper instances are recognized via their shared dxnType
prototype tag.
A stable string encoding of a DXN value, equal for and only for
dxnEquals-equal values. Used internally for structural dedup/sort (e.g.DXNSortedSet's uniqueness invariant) and as a deterministic tiebreaker for kinds with no natural element order (map/set).