In California, Uber, Lyft, TaskRabbit, and a half-dozen other companies are lobbying to defang a court ruling that could make it difficult to avoid reclassifying such workers as employees. And in Washington, the Republican-dominated National Labor Relations Board has made moves to undo an Obama-era precedent that could make big employers legally liable for contract workers even if they have only indirect control over them.The GOP takeover in Washington is one reason the Temporary Workers of America, a union of bug testers for Microsoft Corp., gave up on what had been, for people in the software world, an almost unheard of unionization victory, says the group’s founder, Philippe Boucher.