There are heroes in schools who don’t show up in assemblies, whose pictures don’t make it onto the Wall of Fame in the front office, and who rarely get mentioned in speeches. They’re not on the gym wall. And they’re not in the yearbook’s “spotlight” section. But if they ever took a day off, you’d hear about it before first bell. I’m talking about our school nutrition professionals: the lunch ladies; the kitchen crews; the early-morning slicers, …