Flag heat-pump fuel-39 + MVHR-heat-recovery gaps for manual review

Autonomous-run triage of the moderate eng-vs-lodged gaps resolves them into two
patterns, both flagged for owner review (not auto-fixable):
- Heat-pump fuel code 39 mis-priced as gas (over-rates; both gap directions).
- MVHR heat recovery modelled as plain extract loss → systematic UNDER-rating
  (~8-12 SAP) on every full-SAP cert carrying a mechanical_vent_system_index_number.
  New memory mvhr-heat-recovery-not-modelled; needs the Appendix Q / PCDB MVHR
  efficiency model.
findings doc updated with the classification.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/hyde/autonomous_run_findings.md

@@ -1,5 +1,15 @@
 # Autonomous corpus run — findings for review (2026-06-16)
 
+> ## 🚩 MANUAL REVIEW NEEDED — heat-pump fuel code 39 mis-priced (CALCULATOR)
+> **Owner action required.** Database heat-pump certs (fuel code 39) are priced
+> at the **gas** rate instead of electricity → SAP over-rated by ~14
+> (uprn_10093114053: eng 93 vs lodged 79). Root cause + evidence in §"BUGS" below
+> and memory `heat-pump-fuel-39-mispriced`. NOT auto-fixable: the correct
+> electricity tariff for a database heat pump (standard code 30 vs a heat-pump
+> tariff) is a SAP-domain judgement and it touches the Table-12a off-peak split.
+> Decide the tariff, then it's a normal TDD fix. Affects every fuel-39 cert.
+
+
 Triaged the full remaining worklist (~95 UPRNs): capture → map → engine SAP,
 flagging |eng−lodged| ≥ 8. Most certs map within ±4 of lodged.
 
@@ -44,12 +54,27 @@ metres → multi-million-m² windows → HTC in the millions → **SAP clamps to
   `heat-pump-fuel-39-mispriced`. Needs SAP-domain confirmation of the correct
   electricity tariff (standard 30 vs heat-pump) → not an autonomous fix.
 
-## ⚠ MODERATE eng-vs-lodged gaps (not catastrophic — sample, for review)
-Direction is mostly engine UNDER lodged on full-SAP (17.0/17.1) certs:
-- −15: uprn_100090108846 (RdSAP-20, off-peak fuel 29), uprn_100061086424 (RdSAP-17.0)
-- −12: uprn_10090343767 (17.0)   ·  −9: uprn_10090341811, 10093386427  ·  +9: uprn_10090342180
-- A spread of −6…−8 on 17.0/17.1. Likely a mix of the full-SAP→RdSAP residual and
-  possibly more heat-pump-fuel cases. Worth a focused pass after the 2 bugs above.
+## ⚠ MODERATE gaps — now CLASSIFIED into two patterns
+
+### Pattern A — heat-pump fuel-39 / high-COP certs (= bug #2, both directions)
+- uprn_10090342180 (fuel 39): +9 (over-rates, classic fuel-39 mispricing)
+- uprn_10093388053 (fuel 39): −7   ·  uprn_100090108846 (fuel 29 HP, COP 3.44): −15
+- All resolve once the heat-pump fuel pricing is fixed (🚩 review item above).
+
+### Pattern B — 🚩 MVHR heat recovery NOT modelled — CALCULATOR gap (NEW, REVIEW)
+Full-SAP **gas** certs that UNDER-predict −6…−12 ALL carry an **MVHR system index**
+(`mechanical_vent_system_index_number` 500352 / 500230 / 500438 …). MVHR recovers
+exhaust heat (big SAP boost), but the engine models mechanical ventilation as
+**extract heat loss, not heat recovery** (same as the worked-ref note: "decentralised
+MEV → EXTRACT_OR_PIV_OUTSIDE, priced as extract loss"). So every MVHR cert is
+systematically under-credited.
+- uprn_10090343767 (−12), 10090341811 (−9), 10093386427 (−9), 202211170 (−7),
+  10091636116 (−8), 10093049867 (−6), 10090034761 (−6), 10091636031 (−6).
+- Needs the SAP Appendix Q / PCDB MVHR heat-recovery efficiency model — a feature,
+  not a one-line fix. See memory `mvhr-heat-recovery-not-modelled`.
+
+### Other
+- uprn_100061086424 (RdSAP-17.0, fuel 29, −15): not yet diagnosed (off-peak electric).
 
 ## NOT diagnosed individually
 The ~70 within-±4 certs are not listed; they look healthy.