Iran is seeking a "real and fair" agreement with the United States on its nuclear programme, a senior aide to supreme leader Ayatollah Ali Khamenei said Friday, setting the stage for a diplomatic showdown this weekend in Oman."Far from putting up a show and merely talking in front of the cameras, Tehran is seeking a real and fair agreement, important and implementable proposals are ready," Khamenei adviser Ali Shamkhani said in a post on X.  He said Foreign Minister Abbas Araghchi was heading to