The United States Treasury Department has authorized passenger ferry services to Cuba for the first time in more than a half-century, in a major step in improving relations between the two countries. At least four companies said they were notified Tuesday of approvals by the U.S. Treasury and Commerce departments, the first since Washington imposed a trade embargo on Cuba. Licensed were Havana Ferry Partners of Fort Lauderdale, Baja Ferries of Miami, United Caribbean Lines Florida of Greater Orlando and Airline Brokers Co. of Miami and Fort Lauderdale. The proposed ferry services must still obtain Havana’s approval, lawyers for the companies said, but that the U.S. move clears the way for negotiations.