Per-cell useResolvedPages([id]) calls each mounted with a unique
React Query key, so a grid with 20 page-typed cells fired 20 requests on
first paint. A shared loader now accumulates incoming ids within a
microtask, fires a single POST for the union, and fans the subset each
caller asked for back to them. Cells keep their own cache entry + null
handling; they just share the underlying network call.
Also renames /bases/pages/resolve → /bases/pages/expand — the old name
collided with other "resolve" semantics in the codebase.
