WASHINGTON – President Donald Trump’s lawyers and special counsel Robert Mueller are hurtling toward a showdown over a yearlong investigation into the president’s conduct, with Mueller pushing to write up his findings by summer’s end and Trump’s lawyers strategizing how to rebut a report that could spur impeachment hearings. The confrontation is coming to a head as Trump and his allies ratchet up their attacks on the special counsel probe, seizing on a report released Thursday by the Justice Department’s inspector general that castigated FBI officials for their conduct during the 2016 Hillary Clinton email investigation. Rudy Giuliani, the president’s personal attorney, said that he planned to use the inspector general’s conclusions to undermine Mueller, suggesting he may ask Attorney General Jeff Sessions to appoint a second special counsel to examine the current probe. “We want to see if we can have the investigation and special counsel declared illegal and unauthorized,” Giuliani said in an interview Friday. In the meantime, Trump must decide whether to do a face-to-face interview with Mueller’s team – an answer the president’s legal team expects to have in the next two weeks. If the president agreed to a sit-down, the special counsel has told Trump’s lawyers that he could finish within roughly 90 days a report on whether Trump sought to obstruct a probe into Russian interference in the 2016 campaign, according to two people familiar with the discussions.