Every morning, Valerie Gilbert, a Harvard-educated writer and actress, wakes up in her Upper East Side apartment; feeds her dog, Milo, and her cats, Marlena and Celeste; brews a cup of coffee; and sits down at her oval dining room table. Then, she opens her laptop and begins fighting the global cabal. Ms. Gilbert, 57, is a believer in QAnon, the pro-Trump conspiracy theory. Like all QAnon faithful