nx_seat_hub_gate.nx

nx_seat_hub_gate.nx -- GATE for the S2b hub-frame wrapper (5 teeth, 3 negative controls). PREREQ: stage first: _offc/nx_seat_hub.elf + _offc/nx_fix_echo.elf. Run from nxc2 root. The wrapper is judged OFFLINE against controlled bodies (nx_fix_echo stands in for nx_mcp_call; hubconf mcpelf= points at it, capfile= is a dummy) -- the LIVE hub tooth is a separate one-shot run (network gates flake; live proof is banked, not gated). SELF-EXEC CHAIN (one wrapper fork per process): argv = [self] [stage] [pass]. Teeth: T1 checkin HELD accepted | T2 NEG checkin CONTENDED refused | T3 NEG garbage/empty body refused | T4 checkout done=1 accepted | T5 NEG checkout marker-absent refused. Verdict: NX-SEAT-HUB-GATE pass=N/5 verdict=GREEN|RED (exit 0 iff 5/5). license_tier: ORIGINAL No hw writes (Rule 26).