textAvatarHashColor function
Stable fallback when no palette match exists.
Implementation
Color textAvatarHashColor(String input) {
if (input.isEmptyOrNull) return Colors.grey;
final hue = input.hashCode.abs() % 360;
return HSLColor.fromAHSL(1, hue.toDouble(), 0.55, 0.48).toColor();
}