On a Thursday afternoon at the Daley Center, Diann K. Marsalek addressed a man with a DUI charge whose T-shirt read “Life is Rum.” Not that she could see it. The phrase was on the back of the shirt, along with a drunken stick figure hoisting a goblet. Since becoming the supervising judge of Cook County Circuit Court’s traffic court in May, Marsalek has overseen a court with many judges — herself included — regularly pulling duty in two rooms. She oversees eight to 20 judges, depending …