Visible
data class VisibleGeoBounds(val west: Double, val south: Double, val east: Double, val north: Double)
Geographic rectangle in degrees (WGS84), same convention as Mapbox camera bounds.
fromMapboxUnwrappedCamera rejects degenerate longitude spans that Mapbox occasionally returns after zoom gestures (unwrapped corners collapse to a narrow strip while latitude stays wide), which otherwise clips wind fill and encoded-grid symbols to a vertical band.