resolvewalk N_MLET arm distributes the N_IDENT-callee rhs return-tuple element types onto unannotated bindings (the A-narrow slice). Byte-id- neutral — cgen still classifies structurally, stamps inert until the exprfloatkind collapse. N_DOT-callee destructure deferred to #16/#17. Prereq for the #121 collapse (commits 2/3).