New York is in an economic death spiral as companies and taxpayers flee, taking their money with them. Bruce Blakeman needs to go bold. So far, the Republican challenger in this November’s race for governor has been running a run-of-the-mill campaign, trading barbs with Gov. Kathy Hochul but advancing few big ideas.     Come on, Bruce. Offer New Yorkers real change: Roll out a concrete plan to phase out the state’s personal income tax. It’s the economy killer. The Albany spendaholics — in both