New York Fantasy Sports sites FanDuel Inc. and DraftKings Inc., already facing mounting legal and regulatory scrutiny, ran into more trouble when Citigroup said it was blocking transactions by New York state residents. The move by the world’s largest credit-card lender added to the pressure in New York, the heart of the fantasy-sports industry’s legal woes since Attorney General Eric Schneiderman sued the companies in November. Schneiderman contends that daily fantasy sports are a form of gambling, which is illegal in New York. The firms say they offer games of skill, and are accepting New Yorkers’ business as while the…