deleteLayer method
Implementation
void deleteLayer(String layerId) {
if (_currentTemplate == null) return;
final updatedLayers = _currentTemplate!.layers
.where((layer) => layer.id != layerId)
.toList();
_currentTemplate = _currentTemplate!.copyWith(layers: updatedLayers);
if (_selectedLayer?.id == layerId) {
_selectedLayer = null;
}
notifyListeners();
}