A Korean-American novelist’s new book focuses on two families’ reckoning of the 1992 L.A. riots — Steph Cha told me she wanted to write about the L.A. she knew. Her new novel, Your House Will Pay, is a literary thriller that intertwines the fates of two families from a murder. The novel is told through the perspectives of its protagonists: Grace Park is a sheltered, second-generation…