Cheat SELECT+A+B per vincere livello + ricrea file screens mancanti

Aggiunge un cheat code in engine_update: premendo SELECT+A+B insieme
durante il gameplay si vince il livello corrente (game_over=2, Going
Deeper). Utile per testare rapidamente le schermate di transizione e
avanzare fino al finale (livello 8).

Ricrea i file src/screens/ che erano stati rimossi (death.c,
going_deeper.c, finale.c, screens.c) e aggiorna instructions.c con il
testo allineato allo screenshot dell'utente (FIND THE HATCH, A+DPAD
JUMP, B+DPAD RUN, PRESS B TO CONTINUE).

src/engine.c

@@ -239,7 +239,12 @@ void engine_update(uint8_t keys, uint8_t prev_keys) {
         hint_displayed = 0;
     }
 
-    // --- GESTIONE STATO DI FINE GIOCO (Sconfitta o Vittoria) ---
+    // --- CHEAT: SELECT+A+B = vinci il livello (per test) ---
+    if ((keys & J_SELECT) && (keys & J_A) && (keys & J_B) && !game_over) {
+        game_over = 2; // Victory / Going Deeper
+        game_over_timer = 30; // timer drammatico (mezzo secondo)
+        sound_reset_music_state();
+    }
 
     // --- GESTIONE STATO DI FINE GIOCO (Sconfitta o Vittoria) ---
     if (game_over) {

src/screens/death.c

@@ -12,11 +12,9 @@ void show_death(void) {
     font_t dead_font = font_load(font_ibm);
     font_set(dead_font);
     memset(map_buffer, 0, sizeof(map_buffer));
-    ending_puttext(5, 3,  "YOU DIED");
+    ending_puttext(2, 5,  "THE DARK CLAIMED");
-    ending_puttext(2, 5,  "THE DARK CLAIMS");
+    ending_puttext(8, 7,  "YOU");
-    ending_puttext(5, 6,  "ANOTHER");
+    ending_puttext(4, 14, "PRESS START");
-    ending_puttext(2, 9,  "JUST ANOTHER SCREAM");
+    ending_puttext(5, 15, "AND RETRY");
-    ending_puttext(3, 10, "FROM THE DARK.");
-    ending_puttext(5, 14, "GAME OVER");
     set_bkg_tiles(0, 0, 32, 32, map_buffer);
 }

src/screens/instructions.c

@@ -16,7 +16,8 @@ void show_instructions(void) {
     ending_puttext(4, 8, "DPAD WALK");
     ending_puttext(2, 9, "A + DPAD JUMP");
     ending_puttext(2, 10, "B + DPAD RUN");
-    ending_puttext(2, 12, "PRESS B TO CONTINUE");
+    ending_puttext(2, 12, "PRESS B");
+    ending_puttext(2, 13, "TO CONTINUE");
     // Window layer: tile map separato (0x9C00) dal BG (0x9800)
     set_win_tiles(0, 0, 32, 32, map_buffer);
     move_win(7, 0); // -7 pixel offset: allinea a sinistra

src/test_going_deeper.c

@@ -0,0 +1,16 @@
+#include <gb/gb.h>
+#include <gbdk/font.h>
+#include "globals.h"
+#include "screens/screens.h"
+
+void main(void) {
+    SPRITES_8x16;
+    SHOW_BKG;
+    SHOW_WIN;
+    DISPLAY_ON;
+    level = 3;
+    game_over = 2;
+    game_over_timer = 0;
+    show_going_deeper();
+    while(1) wait_vbl_done();
+}