nx_connect_match_lib.nx

nx_connect_match_lib.nx -- the RECIPROCAL language-exchange match engine, extracted as a shared library so the verifying gate (nx_connect_match) and the LIVE app (nx_connect_serve /partners) bind ONE implementation of the law. Before this split the live page printed HARDCODED scores while claiming they came from "the gated match engine" -- the page asserted a computation it never ran. No main, no syscalls, no allocation, so any consumer can import it. THE LAW: language exchange is COMPLEMENTARY, not similarity. A good partner TEACHES what you want to LEARN and LEARNS what you can TEACH, so the core signal is a HARMONIC MEAN of the two directional fits -- if either direction is zero the pair collapses to zero, which is what makes reciprocity NECESSARY rather than merely preferred. Shared interests modulate but can never rescue a one-sided pair. Integer only, no floats. The output is an INTERNAL RANK WEIGHT 0..100 and must never be presented as a compatibility score (Joel & Eastwick, PNAS 2020: partner traits explain ~5% of long-term variance). SAFETY BY CONSTRUCTION: the dating/romance lane is UNREACHABLE to or from a minor in BOTH directions, even when the underlying reciprocal score is perfect, while language exchange stays fully open to them. license_tier: ORIGINAL