Kat’s between a bloc and a hard place. Gov. Kathy Hochul’s already on the re-election hot seat as liberal pols and activists warned her Sunday to support Mayor-elect Zohran Mamdani’s tax-hike plans — or get voted out of office. The Democratic Socialists of America — empowered and gaining mainstream influence after Mamdani’s win in the mayoral election this month — held a “Tax the Rich” rally in Union Square Sunday as Democratic state lawmakers warm to the tax increases over worries they could