New Twitter owner Elon Musk warned on Wednesday that all of the platform’s staff must be “extremely hardcore” or face firing. Employees learned in a midnight email, obtained by the Washington Post, they had until Thursday to decide whether they wanted to remain with the social media company. Those interested in working on Musk’s new iteration of Twitter were instructed to click a link in the email, and those who fail to do so by the deadline would automatically be dismissed with three months of severance pay. “Going forward, to build a breakthrough Twitter 2.0 and succeed in an increasingly co...