lib/minikanren/stream.sx: mzero/unit/mk-mplus/mk-bind/stream-take. Three
stream shapes (empty, mature list, immature thunk). mk-mplus suspends and
swaps on a paused-left for fair interleaving (Reasoned Schemer style).
lib/minikanren/goals.sx: succeed/fail/==/==-check + conj2/disj2 +
variadic mk-conj/mk-disj. ==-check is the opt-in occurs-checked variant.
Forced-rename note: SX has a host primitive `bind` that silently shadows
user-level defines, so all stream/goal operators are mk-prefixed. Recorded
in feedback memory.
82/82 tests cumulative (48 unify + 34 goals).