SEOUL, SOUTH KOREA — Impeached South Korean President Yoon Suk Yeol was in court for the first time Saturday for a crucial hearing that will decide whether to extend his detention as investigators probe his failed martial law bid. Yoon’s supporters rallied outside the court and scuffled with police as he arrived in a blue van, weeks after throwing the nation into chaos by attempting to suspend civilian rule. The president’s Dec. 3 martial law bid lasted just six hours, with lawmakers voting it down despite him ordering soldiers to storm parliament to stop them. Yoon was subsequently impeached by