SEOUL, South Korea—At an unusual North Korean parade showcasing military dogs and virus workers in orange hazmat suits, leader Kim Jong Un still stood out by looking thinner and more energetic than he has in years. During the event that started late Wednesday, Kim, wearing a cream suit and a shiny white tie, emerged as the clock struck midnight. He beamed in response to thunderous applause from performers and spectators filling Pyongyang’s brightly illuminated Kim Il Sung Square, named after his grandfather and founder of the nation on its 73rd anniversary. He smiled widely, waved to the crowd, and kissed children who presented him with flowers before taking his spot on a balcony to observe the parade. He laughed vigorously and applauded the marchers throughout the event while chatting animatedly with senior officials. It was a stark change from 2018, when TV footage showed him struggling to catch his breath …