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.

research/commercial-identity/lei-gleif-legal-entity-identifier.md

@@ -51,7 +51,9 @@ requirements.
 
 ## Identity-Canon Implications
 
-- LEI maps to **Identifier** for **Legal Entity** / **Organization** actors.
+- LEI maps to **Registry Identifier** (`scheme: 0199`, `authority_class:
+  regulatory_global`, `renewal_required: true`) for **Legal Entity** /
+  **Organization** actors.
 - Level 2 parent data maps to **Ownership** or structural Organization relationships.
 - LEI record maps to **Commercial Record** or authoritative **Identity Record**
   with registry **Evidence Source**.
@@ -70,7 +72,7 @@ requirements.
 
 | LEI concept | Candidate canonical concept |
 | --- | --- |
-| LEI code | Identifier (authoritative, global) |
+| LEI code | Registry Identifier (regulatory_global, ICD 0199) |
 | Legal entity | Legal Entity / Organization |
 | Level 1 data | Commercial Record / registry Profile |
 | Level 2 parent | Ownership Relationship |
@@ -80,8 +82,12 @@ requirements.
 
 ## Open Questions
 
-- Should authoritative registry identifiers (LEI, company reg number) be a distinct
-  Identifier subtype with renewal semantics?
+- Synonymity strength when linking LEI to DUNS or national company reg numbers.
+
+## Resolved (see registry-identifier-subtypes.md)
+
+- Authoritative and proxy registry IDs → **Registry Identifier** subtype with
+  authority class and renewal lifecycle.
 
 ## References