Every Sanity marketing site ends up with a page builder. An array of sections, an insert menu, a render loop that maps block._type to a component. You've built it. I've built it. We've all built the same thing. And every one of them ships with the same bug. You add a new section. You wire it into the schema. You add a renderer. You add a component. You add the type. And then — because there are five places to touch and you're a human — you forget one. The section renders blank in produ...