Normalize RdSAP main_heating_controls mapping on the degraded 17.0 path

PRD #1385, heating-controls family. The 17.0 API mapper omitted
main_heating_controls entirely, leaving the domain field None while the
19.0/20.0/21.x paths map the first lodged control via _map_energy_element. 17.0
lodges main_heating_controls (List[EnergyElement]) in all 23 local fixtures.

The mapped element is the same EnergyElement type 17.0 already carries for
main_heating / window, so this is straight parity (not new logic). Guarded on a
non-empty list -> None, matching the siblings.

Verification: new test 2 passed; test_mapper_corpus 6002 passed; recommendation
+ heating-control tests 85 passed (the domain EnergyElement field is distinct
from the subscriptable dict HeatingControlRecommender reads via the Property
wrapper, so no recommender destabilisation); SAP-accuracy regressions pass;
pyright unchanged (39 -> 39, pre-existing).

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

datatypes/epc/domain/mapper.py

@@ -612,6 +612,17 @@ class EpcPropertyDataMapper:
             main_heating=EpcPropertyDataMapper._map_energy_elements(
                 schema.main_heating
             ),
+            # First control system if multiple — mirrors the 19.0/21.0.1 paths.
+            # 17.0 lodges main_heating_controls (List[EnergyElement]) but omitted
+            # it, leaving main_heating_controls=None so the heating-control
+            # recommendations (programmer/room-stat/TRVs) had nothing to read.
+            main_heating_controls=(
+                EpcPropertyDataMapper._map_energy_element(
+                    schema.main_heating_controls[0]
+                )
+                if schema.main_heating_controls
+                else None
+            ),
             window=EpcPropertyDataMapper._map_energy_element(schema.window),
             lighting=EpcPropertyDataMapper._map_energy_element(schema.lighting),
             hot_water=EpcPropertyDataMapper._map_energy_element(schema.hot_water),

tests/datatypes/epc/domain/test_mapper_main_heating_controls_17_0.py

@@ -0,0 +1,48 @@
+"""Regression: the RdSAP-Schema-17.0 mapper path must carry the lodged
+main_heating_controls, like every other API path (19.0/20.0/21.x).
+
+PRD #1385 (mapper normalization). 17.0 lodges `main_heating_controls`
+(List[EnergyElement]) but the mapper omitted it, leaving the domain field None
+while the 19.0/21.0.1 paths map the first control via `_map_energy_element`. The
+mapped element is the same EnergyElement type 17.0 already carries for
+`main_heating` / `window`, so this is straight parity.
+"""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+from typing import Any
+
+from datatypes.epc.domain.mapper import EpcPropertyDataMapper
+
+# 17.0 cert lodging a main-heating control ("Programmer, TRVs and bypass").
+_FIXTURE = Path("tests/fixtures/epc_prediction/PE71NT/cert-26619d8e7f8e.json")
+
+
+def _load() -> dict[str, Any]:
+    data: dict[str, Any] = json.loads(_FIXTURE.read_text())
+    assert data["schema_type"] == "RdSAP-Schema-17.0"
+    return data
+
+
+def test_17_0_maps_lodged_main_heating_controls() -> None:
+    data = _load()
+    assert data["main_heating_controls"], "fixture must lodge a control"
+
+    epc = EpcPropertyDataMapper.from_api_response(data)
+
+    # Was None on the 17.0 path; now carries the first lodged control element.
+    assert epc.main_heating_controls is not None
+    assert epc.main_heating_controls.description == "Programmer, TRVs and bypass"
+    assert epc.main_heating_controls.energy_efficiency_rating == 3
+
+
+def test_17_0_no_controls_maps_to_none() -> None:
+    # An empty control list maps to None (no phantom element), like the siblings.
+    data = _load()
+    data["main_heating_controls"] = []
+
+    epc = EpcPropertyDataMapper.from_api_response(data)
+
+    assert epc.main_heating_controls is None