heroForAccessible function
hero repaired for the Accessible lock (labels and display text
≥ 7:1). Returns hero unchanged when accessible is false.
Implementation
ThemeSpec heroForAccessible(ThemeSpec hero, {bool accessible = true}) {
if (!accessible) return hero;
final locked = hero.copyWith(accessible: true);
return repairTheme(locked) ??
(throw StateError('hero ${hero.heroId} cannot reach 7:1'));
}