fix: expose hasMore in offset infinite scroll query

[psteinroe]

• Add hasMore to useOffsetInfiniteScrollQuery return types and hook output
• Keep loadMore nullable and derive availability from the hook's one-extra-row pagination state
• Update docs to describe hasMore and clarify that loadMore() is null when no more data exists
• Extend tests to verify hasMore toggles correctly and loadMore disappears on the last page

[changeset-bot]

🦋 Changeset detected

Latest commit: fc8daee

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@supabase-cache-helpers/postgrest-swr	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR