NEW YORK (AP) — Greta Gerwig debuted a first look at “Narnia: The Magician’s Nephew” on Tuesday, previewing a full-hearted adaptation of C.S. Lewis’ allegorical adventure and an IMAX-sized spectacle made for Netflix but designed for the big screen. Led Zeppelin’s “Stairway to Heaven” scores the trailer, which was also released online. A few hours...