FutuRe sample pages no longer stuck on compile errors

The FutuRe sample's per-business-unit Line of Business and Transaction Mapping pages were declared as NodeTypes without any source code, so every deployment parked them on a compilation-error overlay. They now render as ordinary documentation pages, keeping their governance prose and their child nodes. A new build-time guard fails any pull request that ships a NodeType naming a content type its sources cannot provide, so the broken shape cannot return.