Global id of this page's first cluster (clusters are page-contiguous).
LOD level shared by every cluster in the page (pages never cross levels).
Unique vertices in vertexPool.
Page bounding sphere (coarse cull / prefetch).
Coarsest selfError in the page (LOD gating / prefetch).
Packed vertices, PACKED_VERTEX_WORDS u32 each (same words as the global pool).
Cluster-local → page-local vertex index (indexes vertexPool).
Triangle corner → cluster-local vertex index (u8, unchanged).
One self-contained streamable page.