FALL RIVER, Mass. — Aaron Hernandez had it all. Fame, as a star tight end with the New England Patriots, which took him to the Super Bowl. Fortune, with a $40 million NFL contract. Family, with a fiancee and baby daughter. But his future? A lifetime behind bars after being convicted last week of first-degree murder in the 2013 slaying of Odin Lloyd, who was dating the sister of Hernandez’s fiancee. After more than nine weeks of testimony, 135 witnesses and 439 exhibits, the question remains: Why did he …