Pianist Lim Yunchan swept the three most prestigious categories at the BBC Music Magazine Awards in London — recording of the year, newcomer of the year and the instrumental award — all for his debut studio album “Chopin: Etudes,” released last year under the Decca Classics label, according to the organizer on Thursday. It marked the first time since the award’s inception in 2006 that a single album has claimed all three titles. Even more unprecedented: a first-time winner in the newcomer cate