WASHINGTON — As an exceedingly bitter, tight and dark campaign for the presidency moves into its last moments, apprehensive election officials and experts warn Election Day is only the first step. The closing of the polls and end of mail-in voting kick off a nearly three-month process before the next president of the United States is sworn in on Inauguration Day in January. New guardrails were enacted by Congress in 2022 to more fully protect the presidential transition, following the Jan. 6, 2021, mob attack on the U.S. Capitol by Trump supporters and a failed scheme to install fake electors….