(LEAD) U.N. Security Council unanimously adopts harshest-ever sanctions on North Korea

(ATTN: EXPANDS lead; UPDATES with details, background in last 11 paras) NEW YORK, March 2 (Yonhap) -- The U.N. Security Council adopted the harshest-ever sanctions on North Korea on Wednesday, punishing Pyongyang for its defiant nuclear and missile te