He’s been called a post-millennial Schubert. Mohammed Fairouz has composed four symphonies and an opera while still in his 20s. He invokes John F. Kennedy and Anwar Sadat, Seamus Heaney and Yehuda Amichai in his compositions. He sees “illustrious language” as a form of music — and as a way, just maybe, to shift the world on its axis.