Sox play tough on memento Lawyers file suit for '04 Series ball By Jonathan Saltzman, Globe Staff To Red Sox fans, it is priceless -- the baseball that Keith Foulke flipped to Doug Mientkiewicz on an October night in St. Louis last year to clinch the team's first World Series championship in 86 years. Now, 13 months after Mientkiewicz pocketed the ball, the team is playing hardball. Lawyers for the Red Sox filed suit yesterday in Suffolk Superior Court seeking permanent possession of the cherished symbol of suffering redeemed. When the team first tried to claim it, the light-hitting but...