- Add `should_close_window()` method to force window close from UI.
- Replace standalone button with ColumnLayout for proper centering.
- Add "Exit" button that calls `should_close_window()`.
- Update ESC key handling to only close window when game is not running.
- Fix ColumnLayout to respect parent's anchor instead of hardcoded TOP_LEFT.
- Remove unused parameter name in Image::update for consistency.
- Add ColumnLayout widget that arranges children vertically with spacing.
- Refactor Widget::add_child to automatically pass `this` as parent.
- Update DebugCollector to use ColumnLayout for consistent spacing.
- Expose children() accessor in Widget for layout management.