Arts supporters gathered at the Liberty Hotel Saturday night for “Banchetto Musicale,’’ a gala preview of Boston Baroque’s “The Magic Flute.’’ The event raised money for the organization’s programs, including its Classics for Kids series and free concerts. Emcee Joyce Kulhawik followed the dress code on the invitation, which called for “magical attire’’ and feathers. “The Magic Flute’’ will be performed Friday and Saturday at Jordan Hall.