As she started her shift on a recent Tuesday, Ann Kearns said something people say all the time, but it feels different in this room. She said: “You never know.’’ But she does know; it happens. People bet on the concept of “you never know’’ a lot in this state; we spend almost $4.5 billion a year on the lottery. Which means that people actually do hit it big. Kearns meets them all, all the time. In Massachusetts, she’s the St. Peter of scratch tickets.