I haven't read anything.
Using logic,which doesn't always give the right answer....You can use your meal credits anytime during your stay, including the day you check in and the day you check out. I'd assume you mug would also be good from the day you check in through the day you check out. It was already posted mug usage is based on calendar days. That means it's good the entire day you check out, if it's good for part of the day.
That's what makes sense to me, too, but I guess then, my question is the number of calendar days - does the number of calendar days equal the number of nights of your stay, or the number of days including the day you arrive through the day you depart. I would assume/hope it to be the latter, but I haven't been able to find any "official" info on that.