Yulia Navalnaya, the widow of Russian opposition leader Alexei Navalny, said that she would press on with her husband's fight for a free Russia and called on supporters to battle President Vladimir Putin with greater fury than ever. Navalny's death robs Russia's disparate opposition of its most charismatic and courageous leader as Putin prepares for an election that will keep him in power until at least 2030. In a nine-minute video message laced with rage, Navalnaya, 47, said Putin had killed her husband and in doing so had robbed her of a husband and her two children of a father.…