Manhattan’s luxury housing market is quietly edging back toward its mid-2010s swagger after a decade marked by excess, collapse and recovery. And this time, the rebound appears to be powered by real money, not just empty supply. New data shows the borough’s priciest homes are nearly back to their 2016 highs, a milestone last seen during the condo boom that reshaped Manhattan’s skyline. By the end of last year, the median price for a luxury home — defined as the top 10% of the market — hit $6.39 million, according to a new report from Douglas Elliman. Manhattan’s luxury housing...