nx_connect_youth_lib.nx

nx_connect_youth_lib.nx -- the YOUTH-SAFETY VISIBLE-CONTEXT WALL ("two-deep"), extracted as a shared library so the verifying gate (nx_connect_lds_youth) and the LIVE app (nx_connect_serve /events) bind ONE implementation. Before this split the live RSVP path re-stated the rule as an inline `adults >= 2` check -- correct by luck, but a second copy that could drift from the verified one. No main, no syscalls, no allocation. THE INVARIANT (encodes the Church's own "two-deep leadership / never one adult alone with a youth" norm as a HARD information-flow rule rather than a policy page; consumes a verified age BAND, never a self-declared age): * peer<->peer (adult<->adult or minor<->minor): allowed. * a linked GUARDIAN and their own youth: allowed -- parents are never blocked. * a non-guardian ADULT <-> a MINOR: allowed ONLY inside a VISIBLE GROUP carrying >=2 adults. A private 1:1, or a group with a single adult, is DENIED BY CONSTRUCTION. Meetup, Tandem, Match and Facebook all permit the adult->minor private DM this denies. Also: no advertising is ever shown to a minor (COPPA + child dignity; the vertical is free either way). license_tier: ORIGINAL