President Joe Biden grabbed a 6% lead over Trump in a national poll released Wednesday even as a survey of battleground states painted a gloomier picture of his reelection prospects. Biden leads Trump 50% to 44% in their likely presidential election rematch, according to the new Quinnipiac University poll. The survey showed a significant shift toward Biden since a December poll that placed the two candidates as virtually deadlocked. The fresh lead was powered primarily by a growing gender gap as women moved strongly into Biden’s camp. Women backed Biden by a 22-point margin, up from 12 points …