fix(search): expose hasMore so pagination can actually terminate

The search cascade only collects up to its window (offset + limit), so
the API's `total` is a moving target — it reads 50, then 100, then 150
as you page. The web client compared loaded-count against it to decide
whether to show "Load more", which could both hide the button while
hundreds of matches remained and show it past the end. The command now
reports `hasMore` (window filled ⇒ more likely exist; short window ⇒
exhausted), the projection allowlists it, and the search page drives
the button and the "N+ results" status from it. The browse allowlist
also gains the groups/year fields from the WWDC year shapes.