toggleItemSelection method
Selects or deselects an item
Implementation
void toggleItemSelection(int listIndex, int itemIndex, Widget item) {
if (_isDisposed || !_isSelecting) return;
final selection = BoardItemSelection(
listIndex: listIndex,
itemIndex: itemIndex,
item: item,
);
final existingIndex = _selectedItems.indexWhere((s) => s.listIndex == listIndex && s.itemIndex == itemIndex);
if (existingIndex >= 0) {
_selectedItems.removeAt(existingIndex);
} else {
_selectedItems.add(selection);
}
_callbacks?.onSelectionChanged?.call(selectedItems);
}