The juxtaposition was disorienting. This show, the first United States stop of her new tour, highlighted the tensions that bedevil Lady Gaga, especially at this stage of her career. She is titanic when it comes to huge smears of feeling, and also to pulverizing disco-pop. She radiates rawness, and is facile with costuming. But all of these things don’t always go hand in hand, and often Lady Gaga finds herself in various tugs of war with herself — sincerity versus artifice, extravagance versus as