To be Sofia Coppola is to have grown up with certain advantages. The Coppola family tree is a verdant one: Sofia’s grandfather was composer Carmine Coppola; actors Jason Schwartzman and Nicolas Cage are her cousins; and her brother Roman produces her films through the family-run production company American Zoetrope. But lineage alone doesn’t determine who we grow up to become. At 46, Coppola, who has made six delicately distinctive feature films over the past 18 years, has built something of a stealth career.