Fix PPU sprite 0 hit init

src/ppu.c

@@ -11,6 +11,8 @@ void nes_ppu_init(nes_PPU* ppu, nes_PPU_Memory* mem) {
     pal[0] = pal[4] = pal[8] = pal[12] =
         pal[16] = pal[20] = pal[24] =
         pal[28] = 0xFFU;
+
+    ppu->hit_line = -1;
 }