It’s not entirely clear from its cheery social-media presence, but Jonathan Morr’s seven-year-old hamburger restaurant Stand apparently closed down permanently sometime last week. Its website is offline, and it looks a lot like the restaurant’s grills and meat lockers were auctioned off on Monday afternoon. You may remember “Betsy,” Stand Burger’s patriotically painted steer mascot, who abruptly went missing from the premises in 2010, only to turn up unharmed two months later, allegedly in a storage facility for Bryant Park. That crime remains unsolved to this day. Anyway, good-bye, Stand Burger! We’ll always think of your 70-30 lean-to-fat LaFrieda blend with fondness.