Investors rushed for safety, pushing down stocks and lifting the prices of oil, gold and government bonds, after Russia launched a military operation in Ukraine and a Ukrainian official said, “The invasion has begun.” By early afternoon Thursday in Hong Kong, futures tied to the S&P 500, Nasdaq-100 and Dow Jones Industrial Average all stood more than 2% lower. Regional stock indexes also fell sharply, with Hong Kong’s Hang Seng Index dropping more than 3%. Brent crude oil, the global benchmark, topped $100 a barrel for the first time since 2014, with the front-month contract rising as much as 3.3%...