Unjustly, Rossini's radiant final opera of political ideals and fatherly love is known today almost solely for its overture. (Think "The Lone Ranger.") But it has many champions, including Gianandrea Noseda, the music director of the Teatro Regio in Turin, Italy. (Mr. Noseda announced has just announced week that he plans to renew his contract after clashing with the theater's administration.) Mr. Noseda brings the forces of the Teatro Regio to New York for a concert performance, in Italian, with a cast that includes the baritone Luca Scalsi, the soprano Angela Meade and, in one of the most difficult roles in the tenor repertory, John Osborn.