Slice S0380.1: RED — pin cert 0380 Summary cascade against worksheet 88.5104

Adds `test_summary_0380_full_chain_sap_matches_worksheet_pdf_exactly`
plus the `_SUMMARY_000899_PDF` fixture constant. The test pins the
Summary → ElmhurstSiteNotesExtractor → EpcPropertyDataMapper →
cert_to_inputs → calculator chain for cert 0380-2471-3250-2596-8761
(Mitsubishi PUZ-WM50VHA ASHP, PCDB index 104568, semi-detached
bungalow age D, TFA 60.43 m²) against the unrounded SAP lodged on
the `dr87-0001-000899.pdf` worksheet "SAP value" line: **88.5104**.

Opens the Summary-path workstream for the 7-cert ASHP cohort. API
path is already at the spec-precision floor (Δ +0.0594, pinned by
slice 102f). The Summary path becomes the canonical reference once
it closes to 1e-4 — the boiler precedents (cert 001479 worksheet
69.0094, cert 0330 worksheet 61.5993) followed the same Summary-
first ordering.

Diagnostic baseline (printed by the probe in the handover):

  Summary mapper main_heating_category:     None    (expected: 4 / HP)
  Summary mapper main_heating_index_number: 104568  (expected: 104568)
  Summary path SAP: 33.7920  Δ vs 88.5104: -54.7184

Failure mode is exactly what the handover predicts: the Elmhurst
extractor surfaces the PCDB index correctly but leaves
`main_heating_category=None`, so `cert_to_inputs` misroutes off the
Appendix N3.6/N3.7 heat-pump path and lands on a default boiler-ish
cascade. First slice to fix in slice 2: surface
`main_heating_category=4` from the Elmhurst Summary heating block
when the PCDB index resolves to a HP record.

Pyright: 0 errors on the test file. Convention: 1e-4 tolerance per
`feedback_zero_error_strict` and the closed-boiler precedent (no
widening until cascade matches at 1e-3 and the residual is documented).
AAA literal headers per `feedback_aaa_test_convention`. `abs(diff)`
not `pytest.approx` per `feedback_abs_diff_over_pytest_approx`.

Baseline shifts from "669 pass + 10 pre-existing fail" to "669 pass +
11 fail" — the new fail is the forcing function for the workstream.

Refs:
- backend/documents_parser/tests/test_summary_pdf_mapper_chain.py:494
- domain/sap10_calculator/docs/HANDOVER_CERT_0380_SUMMARY_PATH.md

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/documents_parser/tests/test_summary_pdf_mapper_chain.py

@@ -58,6 +58,7 @@ _SUMMARY_000516_PDF = _FIXTURES / "Summary_000516.pdf"
 _SUMMARY_001479_PDF = _FIXTURES / "Summary_001479.pdf"
 _SUMMARY_000897_PDF = _FIXTURES / "Summary_000897.pdf"
 _SUMMARY_000784_PDF = _FIXTURES / "Summary_000784.pdf"
+_SUMMARY_000899_PDF = _FIXTURES / "Summary_000899.pdf"
 
 # GOV.UK EPB API JSON for cert 001479 — the API-path counterpart of the
 # Summary_001479.pdf fixture. Together they drive the API ≡ Summary
@@ -491,6 +492,34 @@ def test_summary_0330_full_chain_sap_matches_worksheet_pdf_exactly() -> None:
     assert abs(result.sap_score_continuous - worksheet_unrounded_sap) < 1e-4
 
 
+def test_summary_0380_full_chain_sap_matches_worksheet_pdf_exactly() -> None:
+    # Arrange — cert 0380-2471-3250-2596-8761 (Summary_000899.pdf /
+    # dr87-0001-000899.pdf) is the first heat-pump cert under per-cert
+    # Summary-path mapper validation: Mitsubishi PUZ-WM50VHA ASHP
+    # (PCDB index 104568), semi-detached bungalow age D, TFA 60.43 m².
+    # Worksheet PDF "SAP value" line lodges unrounded SAP **88.5104**.
+    # API-path cohort already pinned at the ±0.07 spec-precision floor
+    # (SAP 88.5698, Δ +0.0594); the Summary path becomes the canonical
+    # reference once it closes to 1e-4 — same pattern boilers 001479
+    # and 0330 followed. Diagnostic probe at handover baseline: the
+    # Elmhurst mapper surfaces main_heating_index_number=104568 but
+    # leaves main_heating_category=None, so the cascade misroutes off
+    # the heat-pump path and lands at SAP 33.7920 (Δ -54.7184).
+    pages = _summary_pdf_to_textract_style_pages(_SUMMARY_000899_PDF)
+    site_notes = ElmhurstSiteNotesExtractor(pages).extract()
+    epc = EpcPropertyDataMapper.from_elmhurst_site_notes(site_notes)
+
+    # Act
+    result = calculate_sap_from_inputs(
+        cert_to_inputs(epc, prices=SAP_10_2_SPEC_PRICES)
+    )
+
+    # Assert — 1e-4 pin, no widening, no xfail (project memory
+    # `feedback_zero_error_strict`).
+    worksheet_unrounded_sap = 88.5104
+    assert abs(result.sap_score_continuous - worksheet_unrounded_sap) < 1e-4
+
+
 _API_0330_JSON = (
     Path(__file__).parents[3]
     / "domain/sap10_calculator/rdsap/tests/fixtures/golden"