updateEffectPosition method
Implementation
void updateEffectPosition(String id, Duration newStart) {
final index = effectOverlays.indexWhere((e) => e.id == id);
if (index != -1) {
final e = effectOverlays[index];
final duration = e.effectiveEndTime - e.startTime;
final start = newStart < Duration.zero ? Duration.zero : newStart;
effectController.updateEffectPosition(id, start, start + duration);
notifyListeners();
}
}