Non-verbal-reasoning papers with the full subject name in the route

This page provides a subject-based home for the current 11+ non-verbal reasoning paper routes, so the URL and the breadcrumbs both reflect the full subject rather than hiding the paper under a generic mixed mock-test path.

The non-verbal reasoning collection is still smaller than maths or verbal reasoning, but this route creates the same subject-first structure now so it can scale naturally as more NVR papers and practice routes are added.