His secret girlfriend has lots of secret wealth. Russian President Vladimir Putin’s longtime mistress has an estimated net worth of $100 million in “shadow wealth,” including swanky apartments and a yacht, despite her modest background, a trove of newly leaked documents reveal. Svetlana Krivonogikh, 46, has been romantically linked with the Russian strongman since he was still deputy mayor of her hometown of St. Petersburg, and reportedly has a daughter with him. But Krivonogikh — who grew up in a communal apartment — and other Putin cronies have been enriched through shell companies in the Virgin Islands and elsewhere, the...