Last spring, even as Donald Trump’s march back toward the White House dominated public attention, his finances, largely out of view, faced serious threats.His office building in lower Manhattan generated too little cash to cover its mortgage, with the balance coming due. Many of his golf courses regularly lacked enough players to cover costs. The flow of millions of dollars a year from his stint as a television celebrity had mostly dried up.And a sudden wave of legal judgments threatened to devour all his cash.