Deepen beneficial ownership and registry identifier research; resolve canon questions

Add source notes on FinCEN CDD/BOI beneficial ownership and ISO 6523/ALEI
registry identifier subtypes. Resolve OpenQuestions: Beneficial Ownership
Relationship as dedicated type; Registry Identifier and Proxy Commercial
Identifier as Reference layer specializations. Update glossary, conceptual
model, terminology, downstream recommendations, and corpus index.

OpenQuestions.md

@@ -178,13 +178,26 @@ downstream-only.
 
 ### Beneficial Owner modeling
 
-**Status:** Open.
+**Status:** Resolved — **Beneficial Ownership Relationship** as dedicated type.
 
-KYC sources require natural persons behind legal entity customers. Candidate:
-Beneficial Owner as Natural Person + Ownership/Representation with Evidence.
+**Decision:** Model regulated beneficial ownership as **Beneficial Ownership
+Relationship** from **Natural Person** to **Organization** / **Legal Entity**
+customer. Use `ownership_prong`, `control_prong`, `equity_percentage`,
+`control_basis`, and `intermediary_chain` metadata. Keep **Beneficial Owner** as
+a glossary role label for the person, not a participation root.
 
-**Decision needed:** Dedicated relationship type vs. Ownership subtype with
-`beneficial` role metadata.
+**Rationale:** Distinct from corporate parent Ownership (LEI Level 2), operational
+resource ownership (Cerbos), and Representation (authorized signers). FinCEN CDD
+uses dual prongs with trust look-through; collapsing into Ownership subtype would
+collide with authorization and corporate-structure semantics.
+
+**Citations:**
+
+- `research/commercial-identity/beneficial-ownership-kyc-boi.md`
+- `research/commercial-identity/kyc-aml-commercial-identity-binding.md`
+
+**Remaining nuance:** Standard `control_basis` enum across jurisdictions; BOI
+reporting volatility vs. enduring CDD collection obligations.
 
 ### Reputation as canon concept
 
@@ -196,11 +209,23 @@ with temporal scope.
 
 ### Registry identifier subtype
 
-**Status:** Open.
+**Status:** Resolved — **Registry Identifier** subtype with authority classes.
 
-LEI, DUNS, UEI, and company registration numbers share renewal, authority, and
-cross-registry linking needs. Candidate: authoritative **Registry Identifier**
-subtype with renewal Lifecycle State.
+**Decision:** Add **Registry Identifier** as an Identifier specialization in the
+Reference layer. Encode scheme via ISO/IEC 6523 ICD where applicable. Use
+`authority_class` (`government_registry`, `regulatory_global`, `commercial_proxy`,
+`tax`), `renewal_required`, and `lifecycle_state` (esp. LEI annual renewal).
+Add **Proxy Commercial Identifier** for vendor-operated keys (DUNS, ICD 0060).
+Link multiple registry IDs for one entity via **Synonymity Assertion**.
+
+**Citations:**
+
+- `research/commercial-identity/registry-identifier-subtypes.md`
+- `research/commercial-identity/lei-gleif-legal-entity-identifier.md`
+- `research/commercial-identity/duns-commercial-credit-identity.md`
+
+**Remaining nuance:** Synonymity strength bands for LEI ↔ DUNS crosswalks; branch
+OPI modeling under ISO 6523.
 
 ### Payment credential boundary