The game now boots into a menu (Start Game, Hard Mode toggle, Music
toggle) navigated with Up/Down and A/Start, instead of dropping
straight into a match. B returns to the menu from a paused or
game-over state.
Eating a cursed apple inverts the snake's steering for
CURSE_DURATION_TICKS ticks, shown on the top screen while active. The
sprite is a recolored copy of the rotten-apple tile since all existing
sprite tiles are already in use.
Use explicit != 0U comparisons for bitmask checks, static_cast instead
of C-style casts, <cstdint>/<cstdio> instead of the C headers, and
puts() instead of iprintf() for plain strings.
phillip