A judge in New York ordered the release of the first homeless person forcibly hospitalized under Mayor Edward I. Koch's campaign to get more of the mentally ill off the streets. However, the city quickly won a stay. Justice Robert Lippman of state Supreme Court, New York's trial-level court, postponed enforcement of his order for three hours to allow the city to appeal. Appellate Division Justice George Bundy Smith then granted the city's request for a stay pending a full hearing in about two weeks. Lippman ruled the city had failed to prove that Joyce Brown was mentally ill, dangerous or unable to care for herself. Brown, 40, was picked up two weeks ago from the 2nd Avenue sidewalk where she had lived for more than a year.