feat: add custom background rendering and speed scaling features for snake gameplay

include/game_logic.h

@@ -13,4 +13,8 @@ void spawn_apples_rotten(GameState &state);
 void spawn_apples_cursed(GameState &state);
 void tick_status_effects(GameState &state);
 
+uint8_t calculate_intensity_31(const GameState &state);
+uint16_t calculate_timer_freq_mhz(const GameState &state);
+uint16_t calculate_timer_reload(const GameState &state);
+
 #endif