Fans at Madison Square Garden before the start of an Eastern Conference semifinal game between the New York Knicks and the Boston Celtics, in New York, May 14, 2025. With the Knicks on an improbable and magical postseason run this year — the team has won 12 consecutive games and is in the finals for the first time in 27 years — the mystique of the courtside seat has reemerged. (Ye Fan/The New York Times) By SARAH MASLIN NIR New York City has always been a hot-ticket town. Once upon a time…