_obd_pipeline_smoke.nx

_obd_pipeline_smoke.nx -- end-to-end OBD pipeline correctness gate. Proves the OBD predictive-maintenance pipeline works by stitching every layer together + asserting expected outputs: 1. nx_obd2_shim.rx_fn parses a synthetic ISO-TP Mode 01 coolant-temp response -> emits EVT_COOLANT_TEMP event 2. nx_pm_consumer_on_event ingests N drift samples -> eventually classifies as ANOM_DRIFT_UP 3. nx_tm_emit_anomaly serializes verdict to stdout NDJSON Synthetic dataset: coolant temperature rising linearly from 87C to 108C across 100 samples spaced 1 hour apart (~4-day window). Per OBD spec the high threshold is ~105C; the linear drift should cross within the 7-day extrapolation horizon, firing ANOM_DRIFT_UP. Status: SEED v0.1.0. 2026-05-27. WINNER-TIER: EXEMPT (correctness gate per NISHIBENCH_WINNER_STANDARD §antipatterns; smokes are gates not perf claims) INCUMBENTS: n/a (correctness gate) EXEMPTION REASON: correctness validation; no performance claim made Exit-code convention: 0 all assertions PASS 1-9 setup-failure verdicts (memory alloc, init) 10-19 shim-path verdicts (frame parse, event emit) 20-29 consumer-path verdicts (register, on_event, classification) 30-39 telemetry-path verdicts (bus init, emit, sink)