migrat a SDL3 Callback API (SDL_AppInit/Iterate/Event/Quit) (milestone 3)

- main.cpp reescrit amb SDL_MAIN_USE_CALLBACKS
- Director convertit a màquina d'estats amb iterate() i handleEvent()
- Seccions (Logo, Intro, Title, Game) amb iterate() i handleEvent()
- Events SDL enrutats via SDL_AppEvent → Director → secció activa
- Eliminat SDL_PollEvent de iterate(), events via handleEvent()
- Transicions entre seccions gestionades per handleSectionTransition()
- Instructions i Game (demo) delegats frame a frame des de Title

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

source/game.cpp

@@ -2950,7 +2950,6 @@ void Game::iterate() {
             enterPausedGame();
         }
         updatePausedGame();
-        checkEvents();
         renderPausedGame();
     }
 
@@ -2960,7 +2959,6 @@ void Game::iterate() {
             enterGameOverScreen();
         }
         updateGameOverScreen();
-        checkGameOverEvents();
         renderGameOverScreen();
     }
 
@@ -2988,9 +2986,6 @@ void Game::iterate() {
         update();
 #endif
 
-        // Comprueba los eventos que hay en cola
-        checkEvents();
-
         // Dibuja los objetos
         render();
     }
@@ -3001,6 +2996,34 @@ bool Game::hasFinished() const {
     return section->name != SECTION_PROG_GAME;
 }
 
+// Procesa un evento individual
+void Game::handleEvent(SDL_Event *event) {
+    // SDL_EVENT_QUIT ya lo maneja Director
+
+    if (event->type == SDL_EVENT_WINDOW_FOCUS_LOST) {
+        section->subsection = SUBSECTION_GAME_PAUSE;
+    }
+
+#ifdef PAUSE
+    if (event->type == SDL_EVENT_KEY_DOWN) {
+        if (event->key.scancode == SDL_SCANCODE_P) {
+            pause = !pause;
+        }
+    }
+#endif
+
+    // Eventos específicos de la pantalla de game over
+    if (section->subsection == SUBSECTION_GAME_GAMEOVER) {
+        if (event->type == SDL_EVENT_KEY_DOWN && event->key.repeat == 0) {
+            if (gameCompleted) {
+                gameOverPostFade = 1;
+                fade->activateFade();
+                JA_PlaySound(itemPickUpSound);
+            }
+        }
+    }
+}
+
 // Bucle para el juego
 void Game::run() {
     while (!hasFinished()) {