Closes the two documentation gaps from #1456 (follow-up to #1401):
- docs/calibration-guide.md: what calibrate/enroll/train-room actually
enforce, grounded in v2/crates/wifi-densepose-calibration and
wifi-densepose-cli source (not just ADR-135/151 aspirational prose).
Covers the hard 600-frame baseline minimum, per-anchor quality gate
thresholds, the unsolved pet/small-motion presence-detection gap, and
what the empty-room baseline capture actually needs (steady vs silent).
Flags that ADR-135's drift_score/BaselineDrift staleness system is not
implemented in code — only bank.rs's baseline_id STALE check is real.
- docs/trust-and-engine-errors.md: exact trigger conditions for
engine_error_count vs the separate, non-sticky `demoted` privacy-class
flag, where both are exposed (/health/ready and /api/v1/status share a
handler), the real diagnostic gap (no per-cause breakdown, log line is
the closest thing), the WDP_GUARD_INTERVAL_US recovery path for
persistent clock-drift demotion, and an honest "no code path found"
answer on whether a converted HuggingFace model explains engine errors.
Also adds both docs to the README documentation table. No code changes.
