Xanadu studied as conceptual ancestor, not a candidate shard. Yield:
reference-not-copy EDL/xanadoc validates projection+overlay+union;
content-identity bidirectional transclusion; portable span-address
(tumbler) problem logged as adapter-contract architecture for
SHARD-WP-0002. Recorded design-bug boundaries: reject
single-global-docuverse, single-canonical-instance, baked-in economic
policy. Added UC-44/45/46; enriched UC-24/27/29/32.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
