20260903T1428Z relationships design

What. Ratified the relationship design (D16-D21): a relation is a Claim with target_partial_id targeting a partial of the same event; entity-level relationships are query-time traversals through member links, never stored edges; derived active/latent usability is invariant 9. Registry v1 relation types: employment, investment, partnership, governance, plus bounded other (D8 stands). Per-type attribute schemas with nullable validity intervals; validity drives belief, reported_at is the fallback. B2 Claim gained snippet/target_partial_id?/attributes?.

Why. The design had no entity-to-entity edges, so profiles, intro paths, and matchmaking were unanswerable. Model chosen in design review plus one team review round; the claims-with-a-target shape reuses supersession, provenance, judge, and belief machinery once instead of twice, and avoids Orbit's stored-edge and raw-name failure modes. Full rationale and alternatives: docs/design/relationships.md.

Verify. Read docs/design/relationships.md; check D16-D21 exist in docs/decisions.md; check the B2 Claim shape and relation-type registry section in docs/design/interfaces.md; check invariant 9 in docs/design/architecture.md.