AllPages enumerates the union's distinct pages, collapsing chorus (same key
across shards) and equivalence-bound identities into one entry via union-find,
noting divergence when members' bodies differ (collapse acknowledged, not
silent). SiteMap builds the namespace tree from page placements, spanning shards.
Both derived/recomputable and presentation-free.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
