Register the structure-graph round; record Phase 0, the CL widening, and two corrections

New doc legal-structure-graph-round-2026-07-31.md registers Eli's design before
any of it is built: layers ordered by VERIFIABILITY (hard refs have a free
oracle; model relational edges over a given skeleton are endpoint-verifiable;
similarity edges have no oracle and rank last), ablation ladder in build order
led by deterministic edge-following at retrieval time (no model, no tokens, no
round trips), the maud-vs-contractnli/privacy_qa density gap (13.1 vs 0.6-0.8
per 10k chars) as the built-in negative control, and an explicit kill criterion
on gold-graph alignment. Multi-doc comparator deferred: LegalBench-RAG is
single-document by construction and has no bed for it.

Restart plan gains a status section: Phase 0's four fixes, the perDocCap
confound measured at ~16x the composer band, the product-lane decoupling, the
CourtListener widening to 55,504 opinion rows, and two corrections of record -
the "skeleton is blind to subsections" claim was an artifact of the probe that
produced it (toBlock flattens every kind to "section"; nodes carry 2,347
subsections), and the real defect was page-number runs winning the spine
competition and suppressing real headings.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H9ToHYJVDxfeJcJwdzrP2H