The Shein pop-up store in New York this month resembled the e-commerce giant’s website, except picture-perfect. Neutral-toned clothing hung on neat racks, next to party dresses that cost less than the cocktail you might drink while wearing them. Bargain-priced wall art and other home decor created a fantasy of living somewhere chic and stylish, without spending thousands. Like the Shein haul videos that go viral online, the pop-up store sold not just physical items, but also a vision:…