2 modelling_e2e properties failed with KeyError: 'maxArrayPanelsCount'.
Google returns a `solarPotential` block with no array-level sizing fields
(`maxArrayPanelsCount` / `panelCapacityWatts`) for buildings with no usable
solar estimate. `SolarPotential.from_building_insights` hard-indexed those keys
and crashed the whole property.
Fix: the projection now returns Optional and yields None when those fields are
absent — the established "no solar potential" outcome (the orchestrator and
recommendation path already type it Optional and skip solar on None). Existing
callers (`_solar_potential_for`, harness) already assign to Optional.
Regression test + `assert is not None` narrowing on the valid-fixture tests.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Slice 4 of the Solar PV Recommendation Generator (ADR-0026).
`select_conservative_configs` turns Google's full solarPanelConfigs ladder
into up to five competing array configs for the Optimiser: drop north-facing
planes (within 30° of due north, wrap-aware), cap usable panels at ~70% of
maxArrayPanelsCount (imagery misses obstructions; MCS edge setback), collapse
rungs that trim to the same usable size keeping the higher-generation layout,
then sample five spanning min→max by expected generation. Returns () when
nothing usable remains.
Real London example → 5 rungs at 4/12/19/26/34 panels (all ≤34.3 = 70% of
49); synthetic cases pin the north-drop and the 70% cap.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
