nx_hvac_efficiency_test.nx

nx_hvac_efficiency_test.nx -- gate for the independent HVAC efficiency verdict engine. Proves, from canned out-of-band traces (NO sockets, deterministic), that the verdict catches the three defects a "happy" thermostat hides, and that the verdict provably TRACKS the real temperature trajectory (liar-kill) so it cannot be a hard-coded constant. Coverage: - sealed-enum validity gate - S1 EFFICIENT : clean heat recovery, 1 cycle, good rate, tiny overshoot - S2 SHORT_CYCLING : oversized unit cycles 6x in 30 min (vendor hides this) - S3 DEGRADED_CAPACITY: runs 100% duty but barely moves temp (fouled/low charge) - S4 POOR_TRACKING : good rate + low cycling but overshoots setpoint hard - S5 IDLE : never ran -> not a fault, but loud (not "efficient") - S6 INSUFFICIENT_DATA: 1 sample -> loud, never a silent zero verdict - S7 BAD_ARG : invalid mode -> loud - LIAR-KILL : same timing, different indoor trajectory -> response rate AND verdict both move (slow->DEGRADED, fast->EFFICIENT) expect_exit: 0 license_tier: ORIGINAL