SolarPotential carries panel dims + per-segment centre/area 🟩

Enrich each SolarRoofSegment from roofSegmentStats (centre + areaMeters2, keyed
by segmentIndex) and read panelHeightMeters/panelWidthMeters onto SolarPotential
— the geometry the Dwelling-Roof Cap (ADR-0038) needs. All Optional; existing
projection + config-selection tests stay green.

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

domain/modelling/solar_potential.py

@@ -62,6 +62,14 @@ class SolarRoofSegment:
     azimuth_degrees: float
     pitch_degrees: float
     yearly_energy_dc_kwh: float
+    # Per-segment centre + roof-plane area, enriched from the top-level
+    # `roofSegmentStats` (keyed by `segmentIndex`) — the per-config
+    # `roofSegmentSummaries` omit them. Used by the Dwelling-Roof Cap
+    # (ADR-0038) to rank segments by distance from the dwelling and bound the
+    # array by usable roof area. None when the stats block lacks the segment.
+    center_latitude: Optional[float] = None
+    center_longitude: Optional[float] = None
+    area_m2: Optional[float] = None
 
     @property
     def sap_orientation(self) -> int:
@@ -94,6 +102,11 @@ class SolarPotential:
     panel_capacity_watts: float
     max_array_panels_count: int
     configurations: tuple[SolarPanelConfiguration, ...]
+    # Physical panel footprint (Google `panelHeightMeters` / `panelWidthMeters`)
+    # — the Dwelling-Roof Cap (ADR-0038) converts a usable roof-area budget into
+    # a panel count via this. None for partial blocks lacking the fields.
+    panel_height_m: Optional[float] = None
+    panel_width_m: Optional[float] = None
 
     @classmethod
     def from_building_insights(
@@ -111,18 +124,46 @@ class SolarPotential:
             or "panelCapacityWatts" not in solar_potential
         ):
             return None
+        # Per-segment centre + area live on the top-level `roofSegmentStats`,
+        # keyed by `segmentIndex`; the per-config `roofSegmentSummaries` carry
+        # only the panel/orientation fields. Build the lookup once.
+        stats_by_index: dict[int, Mapping[str, Any]] = {
+            int(stats["segmentIndex"]): stats
+            for stats in solar_potential.get("roofSegmentStats", [])
+        }
+
+        def _segment(summary: Mapping[str, Any]) -> SolarRoofSegment:
+            index: int = int(summary["segmentIndex"])
+            stats: Optional[Mapping[str, Any]] = stats_by_index.get(index)
+            center: Mapping[str, Any] = (
+                stats.get("center", {}) if stats is not None else {}
+            )
+            area: Optional[float] = (
+                float(stats["stats"]["areaMeters2"])
+                if stats is not None and "stats" in stats
+                else None
+            )
+            return SolarRoofSegment(
+                segment_index=index,
+                panels_count=int(summary["panelsCount"]),
+                azimuth_degrees=float(summary["azimuthDegrees"]),
+                pitch_degrees=float(summary["pitchDegrees"]),
+                yearly_energy_dc_kwh=float(summary["yearlyEnergyDcKwh"]),
+                center_latitude=(
+                    float(center["latitude"]) if "latitude" in center else None
+                ),
+                center_longitude=(
+                    float(center["longitude"]) if "longitude" in center else None
+                ),
+                area_m2=area,
+            )
+
         configurations: tuple[SolarPanelConfiguration, ...] = tuple(
             SolarPanelConfiguration(
                 panels_count=int(config["panelsCount"]),
                 yearly_energy_dc_kwh=float(config["yearlyEnergyDcKwh"]),
                 segments=tuple(
-                    SolarRoofSegment(
+                    _segment(summary)
-                        segment_index=int(summary["segmentIndex"]),
-                        panels_count=int(summary["panelsCount"]),
-                        azimuth_degrees=float(summary["azimuthDegrees"]),
-                        pitch_degrees=float(summary["pitchDegrees"]),
-                        yearly_energy_dc_kwh=float(summary["yearlyEnergyDcKwh"]),
-                    )
                     for summary in config.get("roofSegmentSummaries", [])
                 ),
             )
@@ -132,4 +173,14 @@ class SolarPotential:
             panel_capacity_watts=float(solar_potential["panelCapacityWatts"]),
             max_array_panels_count=int(solar_potential["maxArrayPanelsCount"]),
             configurations=configurations,
+            panel_height_m=(
+                float(solar_potential["panelHeightMeters"])
+                if "panelHeightMeters" in solar_potential
+                else None
+            ),
+            panel_width_m=(
+                float(solar_potential["panelWidthMeters"])
+                if "panelWidthMeters" in solar_potential
+                else None
+            ),
         )