Add pagination argument to optimize graphql relationships and use in local api

Editor assessment

The subject describes the capability concretely: a pagination argument is added to optimize GraphQL relationships, and the local API adopts it too. Both surfaces are named, so integrators know where the argument applies. The feat type fits, and scope absence is acceptable because the mechanisms are enumerated. No body explains how the pagination curbs over-fetching — the why that would teach — but the change is intelligible alone and the PR reference is conventionally attached. Style is clean apart from length. Good and publishable.