The Chinese-owned social media platform TikTok is battling a potential US ban with the signature tools of American democracy — lawyers, lobbyists and money.TikTok has deployed Washington power brokers and $1,500-an-hour attorneys to fend off a new law barring the app unless its Beijing-based parent, ByteDance Ltd., divests. With a $4.8 million ad campaign, a full-court press on Capitol Hill and the US Constitution, TikTok is in a multifront fight for its survival....