By STACY COWLEY With the mid-June peace agreement between Iran and the United States unraveling, Iran could be aided by the billions of dollars it took in as it shipped oil out of the country after the June deal, a concession granted by the United States. That money will be a strategic advantage for Iran’s leadership if the two countries return to open warfare. As part of the June deal, the United States gave Iran two majwor concessions: It lifted its naval blockade, allowing Iranian ships to…