After its striking post-invasion setbacks, Russia has appointed a new Ukraine war commander, a US official said Sunday. Russia has turned to General Alexander Dvornikov, 60, one of Russia’s most experienced military officers and — according to US officials — a general with a record of brutality against civilians in Syria and other war theaters. The senior official who identified the new commander was not authorised to be identified and spoke on condition of anonymity. But the White House national security adviser, Jake Sullivan, said “no appointment of any general can erase the fact that Russi…