Republican National Committee Chairman Joe Gruters will be headlining the state GOP’s post-primary “Unity Breakfast,” a sign that the small state in deep-blue New England has the attention of the national party. The breakfast will take place on Monday, Sept. 14 at the Grappone Center in Concord. Thanks to New Hampshire’s wildly late primary date (the second-latest in the nation), there are just 56 days between winning the nomination and the Nove…