VILNIUS, Lithuania — Hundreds of Russian emigres gathered in central Vilnius to mourn the late Kremlin critic Alexei Navalny, with many expressing a mixture of anger, sorrow and helplessness. In Lithuania’s capital, a hub for exiled Russian opposition members, the death of one of Russia’s most prominent opposition figures in prison has hit hard. According to Lithuania’s national broadcaster LRT, some 500 Russians gathered at the monument to victims of the Soviet occupation on the city’s main artery Gediminas Avenue to collectively mourn Navalny’s passing. Mourners started coming to lay flowers…