Fade from main menu to gameplay

src/states/MenuState.cpp

@@ -40,6 +40,14 @@ void MenuState::onExit() {
 void MenuState::handleEvent(const SDL_Event& e) {
     // Keyboard navigation for menu buttons
     if (e.type == SDL_EVENT_KEY_DOWN && !e.key.repeat) {
+        auto triggerPlay = [&]() {
+            if (ctx.startPlayTransition) {
+                ctx.startPlayTransition();
+            } else if (ctx.stateManager) {
+                ctx.stateManager->setState(AppState::Playing);
+            }
+        };
+
         auto setExitSelection = [&](int value) {
             if (ctx.exitPopupSelectedButton) {
                 *ctx.exitPopupSelectedButton = value;
@@ -115,7 +123,7 @@ void MenuState::handleEvent(const SDL_Event& e) {
                 }
                 switch (selectedButton) {
                     case 0:
-                        ctx.stateManager->setState(AppState::Playing);
+                        triggerPlay();
                         break;
                     case 1:
                         ctx.stateManager->setState(AppState::LevelSelector);

src/states/State.h

@@ -55,6 +55,7 @@ struct StateContext {
     std::function<void(bool)> applyFullscreen; // Allows states to request fullscreen changes
     std::function<bool()> queryFullscreen; // Optional callback if fullscreenFlag is not reliable
     std::function<void()> requestQuit; // Allows menu/option states to close the app gracefully
+    std::function<void()> startPlayTransition; // Optional fade hook when transitioning from menu to gameplay
     // Pointer to the application's StateManager so states can request transitions
     StateManager* stateManager = nullptr;
 };