The pump glyph in the widget header (both the small single-station face and
the medium list face) was hardcoded green; it now uses the app's fuel
colour wheel — green #30D158 unleaded, yellow #FFD60A premium, cyan
#64D2FF diesel — mirroring the per-fuel pumps in the app's segmented
picker. Palette duplicated in the widget target (Shared is Foundation-only
by design); cross-referenced to StationsView.swift's FuelType.tintColor.