feat(ui): add ComboButton widget and integrate into settings

Introduce ComboButton, a button that cycles through options on click.
Used in SettingsUI for fullscreen, V-Sync, and anisotropic filtering.
Adds texture reload support in SettingsScene and makes Button methods
virtual to allow overriding. Also fixes default mouse_enable to true.

src/CMakeLists.txt

@@ -76,4 +76,5 @@ target_sources(${PROJECT_NAME}
         ui/slider.cpp
         ui/settings_ui.cpp
         scene/settings_scene.cpp
+        ui/combo_button.cpp
 )