Get ready, riders: The long-gestating “ Fourth Wing ” TV adaptation has been ordered to series at Amazon ‘s Prime Video. Based on the best-selling “The Empyrean” romantasy book series from author Rebecca Yarros, “Fourth Wing” is set inside the brutal world of Basgiath War College, where there is only one rule: graduate or die. Twenty-year-old Violet Sorrengail was always expected to live a quiet life — but she’s sent on an entirely different path when her mother, a general in the military,