The renowned chef Thomas Keller will open a new pop-up restaurant, called Ad Lib, on January 21. The temporary eatery will reside within the Royal Oak restaurant at the Silverado Resort and Spa in Northern California’s Napa Valley. Keller—globally recognized for his French Laundry and Bouchon Bakery restaurants, both in nearby Yountville—and his team will focus on classic American dishes, with the attention to quality and detail for which the Thomas Keller Restaurant Group is known. Described by Ad Lib’s chef …