When a Beaux-Arts building is remodeled into a school of music, architectural harmony results.Creating a promising future for classical music is the mission of the San Francisco Conservatory of Music. So it’s not surprising that the conservatory’s new building, which welcomed students in September, juxtaposes the very old with the very new. Local architects SMWM (the firm that restored the San Francisco Ferry Building) preserved just two elements of the original 1914 Young Men’s Institute site—the Beaux Arts facade and an ornate ballroom inside.