Slice S0380.5: surface insulated_door_u_value from Summary §10 'Average U-value'

Closes the three-layer gap that left the Summary mapper producing
`insulated_door_u_value=None` even though Summary §10 lodges
"Average U-value" / "1.20" explicitly on cert 0380:

1. `datatypes/epc/surveys/elmhurst_site_notes.py` — add
   `ElmhurstSiteNotes.insulated_door_u_value: Optional[float] = None`,
   placed in the defaulted-field block so existing fixtures that
   omit the field still construct without changes.
2. `backend/documents_parser/elmhurst_extractor.py` — add
   `_extract_door_u_value` that section-scopes the lookup to
   `_section_lines("10.0 Doors:", "11.0 Windows:")` so the bare
   "Average U-value" label cannot be shadowed by global U-value
   lookups in §7 Walls / §8 Roofs / §9 Floors.
3. `datatypes/epc/domain/mapper.py` — surface
   `insulated_door_u_value=survey.insulated_door_u_value` on the
   `from_elmhurst_site_notes` path. The comment in
   `epc_property_data.py:585` ("Not available in site notes") is now
   outdated for Elmhurst Summary PDFs that lodge the explicit value.

Worksheet anchor (dr87-0001-000899.pdf line ref (26)):

  Doors insulated 1   NetArea 3.7000   U-value 1.2000   A×U 4.4400 W/K

Forcing function (Slice S0380.1): cert 0380 Summary cascade
`doors_w_per_k` moves from 5.1800 to **4.4400 W/K — exact match
against worksheet line ref (26)**. The +0.74 W/K mis-attribution
was the default door-U fall-through that the lodged 1.20 value
silences. SAP moves 88.1981 (Δ -0.3123) → 88.2746 (Δ -0.2358).

Added focused unit test
`test_summary_0380_surfaces_insulated_door_u_value_1_2` that pins
the mapper boundary directly to the worksheet's lodged U-value 1.2,
so future debuggers can localise regressions in the new extractor /
field / mapper path before walking the full chain.

Pyright net-zero across all four edited files:
  datatypes/epc/domain/mapper.py:                32 (baseline)
  datatypes/epc/surveys/elmhurst_site_notes.py:   0
  backend/documents_parser/elmhurst_extractor.py: 0
  backend/documents_parser/tests/test_summary_pdf_mapper_chain.py: 0

Regression suite: 673 pass + 11 fail (vs handover baseline 669 + 10
— net +4 pass for the four GREEN unit tests across Slices S0380.2-5;
the +1 fail vs baseline is the S0380.1 chain test which this slice
moves to Δ -0.2358 but does not yet fully close).

Spec refs:
- SAP 10.2 Table 14 (door U-values: composite-construction default
  cascade is silenced when the assessor lodges an explicit measured
  U on the cert; routed via `insulated_door_u_value`).
- Cert 0380 worksheet dr87-0001-000899.pdf line ref (26) — the
  A×U=4.4400 W/K spec value that this slice closes the Summary
  cascade to exactly.

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

backend/documents_parser/elmhurst_extractor.py

@@ -348,6 +348,20 @@ class ElmhurstSiteNotesExtractor:
         lines = [l.strip() for l in main_body.splitlines() if l.strip()]
         return self._floor_details_from_lines(lines)
 
+    def _extract_door_u_value(self) -> Optional[float]:
+        """Read the §10 Doors block's "Average U-value" lodging.
+        Scoped to the §10..§11 slice so the global "U-value" labels in
+        Walls/Roofs/Floors can't shadow the door reading. None when the
+        PDF omits the line (e.g. all doors recorded as uninsulated)."""
+        lines = self._section_lines("10.0 Doors:", "11.0 Windows:")
+        raw = self._local_val(lines, "Average U-value")
+        if not raw:
+            return None
+        try:
+            return float(raw.split()[0])
+        except (ValueError, IndexError):
+            return None
+
     # RIR surface row: `<name>  <length>  <height>  [<insulation>  [<ins_type>]
     #   [<gable_type>]  <default_u>  <known>  <u>]`. The middle slot
     # widths vary by surface kind; we match the four leading numerics
@@ -1203,6 +1217,7 @@ class ElmhurstSiteNotesExtractor:
             floor=self._extract_floor(),
             door_count=self._int_val("Total Number of Doors"),
             insulated_door_count=self._int_val("Number of Insulated Doors"),
+            insulated_door_u_value=self._extract_door_u_value(),
             windows=self._extract_windows(),
             draught_proofing_percent=self._int_val("Draught Proofing"),
             ventilation=self._extract_ventilation(),

backend/documents_parser/tests/test_summary_pdf_mapper_chain.py

@@ -564,6 +564,29 @@ def test_summary_0380_surfaces_wall_insulation_thickness_100mm() -> None:
     assert main.wall_insulation_thickness == "100mm"
 
 
+def test_summary_0380_surfaces_insulated_door_u_value_1_2() -> None:
+    # Arrange — cert 0380's Summary §10 Doors block lodges the door
+    # U-value on the "Average U-value" / "1.20" line pair. The dr87
+    # worksheet line ref (26) confirms the spec value: "Doors
+    # insulated 1, NetArea 3.7000 m², U-value 1.2000, A×U 4.4400 W/K".
+    # Without surfacing the lodged U-value the cascade defaults the
+    # door U and overstates `doors_w_per_k` to 5.18 vs worksheet
+    # 4.44 W/K. The comment at
+    # `datatypes/epc/domain/epc_property_data.py:585` claimed the
+    # value was "not available in site notes" — that assertion is
+    # outdated for Elmhurst Summary PDFs which lodge it explicitly.
+    pages = _summary_pdf_to_textract_style_pages(_SUMMARY_000899_PDF)
+    site_notes = ElmhurstSiteNotesExtractor(pages).extract()
+
+    # Act
+    epc = EpcPropertyDataMapper.from_elmhurst_site_notes(site_notes)
+
+    # Assert — float compare with small tolerance (Summary lodges
+    # "1.20" which parses cleanly to 1.2; API lodges 1.2 directly).
+    assert epc.insulated_door_u_value is not None
+    assert abs(epc.insulated_door_u_value - 1.2) < 1e-6
+
+
 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

datatypes/epc/domain/mapper.py

@@ -352,6 +352,7 @@ class EpcPropertyDataMapper:
             open_chimneys_count=survey.ventilation.open_chimneys_count,
             habitable_rooms_count=survey.habitable_rooms,
             insulated_door_count=survey.insulated_door_count,
+            insulated_door_u_value=survey.insulated_door_u_value,
             cfl_fixed_lighting_bulbs_count=survey.lighting.cfl_count,
             led_fixed_lighting_bulbs_count=survey.lighting.led_count,
             incandescent_fixed_lighting_bulbs_count=survey.lighting.incandescent_count,

datatypes/epc/surveys/elmhurst_site_notes.py

@@ -340,6 +340,13 @@ class ElmhurstSiteNotes:
     # (preserves backward compatibility with the existing fixture).
     extensions: List[ExtensionPart] = field(default_factory=lambda: [])  # type: ignore[reportUnknownLambdaType]
 
+    # §10 "Average U-value" — lodged when at least one door is
+    # insulated. None when the line is absent from the PDF. Defaulted
+    # so existing fixtures that omit it continue to construct without
+    # changes; the API mapper surfaces this same field directly from
+    # the EPC schema.
+    insulated_door_u_value: Optional[float] = None
+
     # §8.1 Rooms in Roof — Main property only in the observed corpus.
     # When None the dwelling has no RR storey (a 2-storey house with a
     # cold loft instead of a room-in-roof). The mapper translates the