toneLift property
Small-shape shadow lift (Task 17d / 8b, fitted on dark regular glass):
after the tone LUT each channel gains toneLift × size × max(0, 1 − c / toneLiftKnee)², with size = max(0, 1 − halfMin / toneLiftSizeRef). SwiftUI lifts the dark end behind small dark glass
(a capsule over a dark photo reads grey, not black). 0 disables it.
Implementation
final double toneLift;