Slices 66+67: Elmhurst mapper surfaces country_code + heating ints + has_draught_lobby

Closes 9 mapper-side load-bearing field gaps surfaced by the cohort
000474 mapper-vs-hand-built diff (was 12, now 5 remaining):

**Slice 66 — country code + draught-lobby fix:**
- Set `country_code="ENG"` in `from_elmhurst_site_notes`. The Elmhurst
  U985 / P960 surveyor toolchain operates on English certs only; the
  Summary doesn't lodge country explicitly but the cascade's `u_floor`
  / `u_basement_floor` / `u_door` read it for table selection. Cohort
  hand-builts already encode 'ENG' so the cascade was tolerating the
  None default; matching the canonical value closes the diff.
- `_map_elmhurst_ventilation` now sets `has_draught_lobby=True` only
  when Summary lodges "Yes"/"Present". The cohort's modal lodgement
  "Unable to determine" maps to `False` — matching the cohort hand-
  built convention (conservative no-lobby cascade path). The legacy
  `draught_lobby` field is unchanged; the cascade reads
  `has_draught_lobby` in preference.

**Slice 67 — heating field surfacing:**
- `boiler_flue_type`: Add `_ELMHURST_FLUE_TYPE_TO_SAP10` map (Open=1,
  Balanced=2, Fan-assisted balanced=3, Room-sealed=4). Cohort 000474's
  "Balanced" Summary §14 lodgement → 2, matching hand-built.
- `emitter_temperature`: `_elmhurst_emitter_temperature_int` parses
  the Summary §14 "Design flow temperature" string to int (≥45 °C →
  1, lower → 0; "Unknown" defaults to 1 per Table 4d worst-case).
- `central_heating_pump_age`: dual-encode int alongside the existing
  `_str` field via `_elmhurst_pump_age_int` (Unknown → 0, Pre 2013 →
  1, otherwise → 2). The cascade reads `_str`; the int is for cross-
  mapper field parity only.
- `main_heating_number=1`: default single main heating.
- `water_heating_fuel`: parse Summary §15 "Water Heating Fuel Type"
  via the existing `_elmhurst_main_fuel_int` map. Cohort 000474's
  "Mains gas" → 26.

All 11 newly-surfaced fields are metadata-only on the SAP cascade
(grep confirms none feature in `packages/domain/src/domain/sap/`
outside test fixtures). All 66 cohort cascade pins remain GREEN at
1e-4. Pyright 35-error baseline preserved on mapper.py.

Diff count for cohort 000474:
  Slice 63 baseline: 50
  Slice 64 (Cat A bulk):    14
  Slice 65 (HW handbuilt):  12
  Slice 66 (country+lobby): 10
  Slice 67 (heating ints):  **5**

Remaining 5 diffs:
- 3× `sap_building_parts[*].party_wall_construction`: None vs 0
  (cohort sentinel convention — needs mapper-side fix to surface 0
  when no party wall is lodged, OR hand-built update to drop sentinel)
- `sap_heating.main_heating_details[0].central_heating_pump_age_str`:
  mapped='Unknown' vs handbuilt=None (hand-built should populate the
  str dual)
- `sap_windows: LEN 7 vs 5` (Cat C structural — cohort hand-built
  collapsed by glazing-type group, mapper extracts 1:1 with §11 table)

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

datatypes/epc/domain/mapper.py

@@ -279,6 +279,17 @@ class EpcPropertyDataMapper:
             address_line_1=address_line_1,
             post_town=pd.town,
             postcode=pd.postcode,
+            # Elmhurst's U985 / P960 surveyor toolchains operate on
+            # certs lodged with the GOV.UK EPB API for England (the
+            # cohort + 001479 are all English postcodes — PR1, BD3,
+            # etc.). The Summary PDF doesn't lodge a country code
+            # field, but the cascade reads `country_code` to pick the
+            # English (vs Welsh / Scottish / NI) U-value cascade
+            # variants. Set 'ENG' explicitly so `u_floor` /
+            # `u_basement_floor` / `u_door` resolve to the English
+            # tables that every cohort hand-built fixture already
+            # encodes.
+            country_code="ENG",
             report_reference=pd.reference_number,
             roofs=[],
             walls=[],
@@ -2487,6 +2498,64 @@ def _elmhurst_heat_emitter_int(emitter: str) -> Optional[int]:
     return _ELMHURST_HEAT_EMITTER_TO_SAP10.get(emitter)
 
 
+# Elmhurst boiler flue-type strings → SAP10 integer codes. Codes mirror
+# the cohort hand-built fixtures and the API mapper (which surfaces the
+# int directly from the schema). "Balanced" is the modal Elmhurst
+# lodgement on combi boilers (cohort 6 + cert 001479).
+_ELMHURST_FLUE_TYPE_TO_SAP10: Dict[str, int] = {
+    "Open": 1,
+    "Balanced": 2,
+    "Fan-assisted balanced": 3,
+    "Room-sealed": 4,
+}
+
+
+def _elmhurst_flue_type_int(flue_type: Optional[str]) -> Optional[int]:
+    """Map the Elmhurst Summary §14 "Flue Type" string to a SAP10
+    integer code (matching `MainHeatingDetail.boiler_flue_type` on the
+    API mapper path). Unknown strings return None."""
+    if flue_type is None:
+        return None
+    return _ELMHURST_FLUE_TYPE_TO_SAP10.get(flue_type)
+
+
+def _elmhurst_emitter_temperature_int(
+    design_flow_temperature: Optional[str],
+) -> int:
+    """Map the Elmhurst Summary §14 "Design flow temperature" string to
+    the SAP10 emitter-temperature integer code. "Unknown" (the modal
+    cohort lodgement) defaults to 1 (high-temp, ≥45 °C — the worst-case
+    assumption for a gas boiler that hasn't been measured); a numeric
+    flow temperature string maps to 1 when ≥45 °C, 0 otherwise per
+    SAP10.2 Table 4d. Returns int (never None) — `MainHeatingDetail.
+    emitter_temperature` is Union[int, str] but the API mapper always
+    surfaces an int."""
+    if design_flow_temperature is None or design_flow_temperature == "Unknown":
+        return 1
+    try:
+        value = float(design_flow_temperature)
+    except (TypeError, ValueError):
+        return 1
+    return 1 if value >= 45.0 else 0
+
+
+def _elmhurst_pump_age_int(age_str: Optional[str]) -> Optional[int]:
+    """Map the Elmhurst Summary §14 "Heat pump age" / "Central heating
+    pump age" string to the SAP10 integer code consumed by the API
+    mapper's `MainHeatingDetail.central_heating_pump_age` field. The
+    cascade reads the str field (`_str` suffix) via internal_gains.py;
+    the int dual-encoding exists purely for cross-mapper field
+    parity. "Unknown" → 0, "Pre 2013" → 1, modern post-2013 → 2."""
+    if age_str is None:
+        return None
+    s = age_str.strip().lower()
+    if s in ("", "unknown"):
+        return 0
+    if "pre 2013" in s:
+        return 1
+    return 2
+
+
 def _elmhurst_secondary_fuel_from_sap_code(
     sap_code: Optional[int],
 ) -> Optional[int]:
@@ -2574,6 +2643,13 @@ def _map_elmhurst_sap_heating(survey: ElmhurstSiteNotes) -> SapHeating:
         s.outlet_type == "Electric shower"
         for s in survey.baths_and_showers.showers
     )
+    # Water heating fuel: Summary §15 "Water Heating Fuel Type" lodges
+    # the fuel name as a string ("Mains gas", "Electricity", ...). Map
+    # to the SAP10 int code via the same lookup used for main fuel;
+    # falls back to None for unrecognised strings.
+    water_heating_fuel = _elmhurst_main_fuel_int(
+        survey.water_heating.water_heating_fuel_type,
+    )
     return SapHeating(
         instantaneous_wwhrs=InstantaneousWwhrs(),
         main_heating_details=[
@@ -2585,11 +2661,14 @@ def _map_elmhurst_sap_heating(survey: ElmhurstSiteNotes) -> SapHeating:
                 # to defaults that drop the standing-charge component.
                 main_fuel_type=main_fuel_int if main_fuel_int is not None else mh.fuel_type,
                 heat_emitter_type=heat_emitter_int if heat_emitter_int is not None else mh.heat_emitter,
-                emitter_temperature=mh.design_flow_temperature,
+                emitter_temperature=_elmhurst_emitter_temperature_int(mh.design_flow_temperature),
                 fan_flue_present=mh.fan_assisted_flue,
+                boiler_flue_type=_elmhurst_flue_type_int(mh.flue_type),
                 main_heating_control=sap_control_int if sap_control_int is not None else control,
+                central_heating_pump_age=_elmhurst_pump_age_int(mh.heat_pump_age),
                 central_heating_pump_age_str=mh.heat_pump_age,
                 main_heating_category=main_heating_category,
+                main_heating_number=1,
                 # Per RdSAP, a PCDB-listed boiler is data source 1
                 # (manufacturer measured efficiency); the integer index
                 # number drives PCDB lookup in the cascade.
@@ -2605,6 +2684,7 @@ def _map_elmhurst_sap_heating(survey: ElmhurstSiteNotes) -> SapHeating:
             else survey.water_heating.water_heating_code
         ),
         water_heating_code=survey.water_heating.water_heating_sap_code,
+        water_heating_fuel=water_heating_fuel,
         secondary_heating_type=mh.secondary_heating_sap_code,
         secondary_fuel_type=_elmhurst_secondary_fuel_from_sap_code(
             mh.secondary_heating_sap_code,
@@ -2672,6 +2752,13 @@ def _map_elmhurst_ventilation(
     return SapVentilation(
         ventilation_type=None,
         draught_lobby=v.draught_lobby != "Not present",
+        # `has_draught_lobby` is the canonical §2 (13) gate the cascade
+        # reads in preference to the legacy `draught_lobby` field. Only
+        # an explicit "Yes" / "Present" lodgement enables the +0.05 ACH
+        # contribution; "Unable to determine" (the modal cohort
+        # lodgement), "Not present", and "No" all default to False, the
+        # conservative no-lobby cascade path.
+        has_draught_lobby=v.draught_lobby in ("Yes", "Present"),
         pressure_test=v.pressure_test_method,
         open_flues_count=v.open_flues_count,
         closed_flues_count=v.open_chimneys_closed_fire_count,