WASHINGTON — In the coming days, the Supreme Court will confront a perfect storm mostly of its own making: a trio of decisions stemming directly from the Jan. 6, 2021 attack on the U.S. Capitol. Within days of each other, if not hours, the justices are expected to rule on whether Donald Trump has immunity from criminal charges over his efforts to overturn his 2020 election defeat and whether Trump supporters who stormed the Capitol can be prosecuted for obstructing an official proceeding. The court also will decide whether former Trump adviser Steve Bannon can stay out of prison while he appeals his contempt of Congress conviction for defying a subpoena from the House committee that investigated the Capitol attack. These cases are among the dozen or so major disputes dealing with abortion, homelessness, the power of federal regulators, the opioid epidemic and social media platforms that the justices have left to decide as the traditional end of their term’s work nears. Taken together, the three cases connected to the former president could feed narratives about the court and its conservative supermajority, which includes three justices appointed by Trump and two other justices, Samuel Alito and Clarence Thomas, who have rejected calls to step away from the Jan.