Breaking down Columbia’s housing shuffle . By Erica Lee   Illustration by Jacqueline Subkhanberdina On the evening of June 30, nearly 160 School of General Studies students opened their inboxes to a puzzling email from Columbia Residential: their residence halls were “no longer available” for the coming school year, with no explanation given. Across the city and the world, Fairholm and Nuss leaseholders were texting and calling frantically.  Every student living in 503 W. 121