WASHINGTON — President-elect Donald J. Trump on Saturday moved to mend fences with political rivals after a divisive campaign, meeting with Mitt Romney, who had scathingly criticized him during the race as “a phony” and “a fraud,” to discuss naming him as secretary of state. The outreach signaled a change in tone one day after Mr. Trump moved to elevate hard-liners to pivotal national security positions. It was not clear whether Mr. Trump would offer the State Department post to Mr. Romney, or whether Mr. Romney, who has broken sharply with him on Russia, free trade and other issues, would...