WASHINGTON — President Trump on Monday headed into a week full of high-stakes meetings with world leaders after spending a 72-hour period banning reporters from the White House, mulling whether it was time to “blow … up” Iran, and proposing to host military drones and snipers at his triumphal arch in the nation’s capital.The weekend — which also included the announcement of a security deal over Greenland and the creation of a new “A.I. Force” — captured an American president operating unpredictably across multiple fronts even as each one drew friction. The actions now stand to color the backdrop of a week…