(Credit: Tatjana Daschel) Ruth Berghaus’s legendary production of “Pelléas et Mélisande” (seen July 9), which has remained in the repertoire of the Staatsoper Unter den Linden since 1991, returned once again to Berlin, proving that genuinely great theatre neither ages nor relinquishes its power to surprise. The evening possessed the aura of an encounter with operatic history: not merely a {…}