Added `billy_drunk.png` for Billy's drunk state. Billy will show the drunk face (red cheeks) when he has 2+ drinks.

**Next Ideas:**
1. **Add more girl states** - Drunk/tipsy versions of Noi's portrait showing different expressions
2. **Add Billy "wasted" state** - An even more extreme drunk Billy image for max drinks

**Ready to level up your game? Pick one and let's build it!**