Add commercial identity research corpus and binding concepts

Record deep research on commercial identity coupling across theory, law,
regulation, and software (KYC, LEI, DUNS, eIDAS, CRM). Introduce Commercial
Commitment, Legal Person, and Beneficial Owner to the canon model and document
the fluid-to-bound identity gradient in the conceptual model.

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

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+# LEI and GLEIF Legal Entity Identifier
+
+## Source Type
+
+Standard and registry. ISO 17442 Legal Entity Identifier; GLEIF global LEI index.
+
+## Domain
+
+Regulated financial markets, legal entity identification, and ownership transparency.
+
+## Why This Source Matters
+
+LEI is the post-2008-crisis global standard for identifying **legal entities** in
+financial transactions. It encodes **who** and **who owns whom**, making it a
+canonical example of commercially binding identity with regulatory renewal
+requirements.
+
+## Key Concepts
+
+- **LEI**: 20-character ISO 17442 identifier for a legal entity.
+- **Legal entity (LEI scope)**: organization participating in financial transactions;
+  individuals cannot obtain LEI.
+- **GLEIF**: Global Legal Entity Identifier Foundation; oversees LOUs and data quality.
+- **LOU (Local Operating Unit)**: issuer/registrar for LEIs in a jurisdiction.
+- **Level 1 data**: business card data — legal name, address, jurisdiction.
+- **Level 2 data**: ownership — direct and ultimate parent relationships.
+- **Renewal**: LEI valid one year; annual renewal required for continued use.
+- **Regulatory mandate**: 45+ jurisdictions require LEI for certain financial reporting.
+
+## Relevant Terminology
+
+| Term | Source meaning |
+| --- | --- |
+| LEI | Legal Entity Identifier code. |
+| Legal entity | Juridical person in financial markets. |
+| Level 1 | Entity reference data. |
+| Level 2 | Parent/ownership reference data. |
+| GLEIF | Global LEI system operator. |
+| LOU | Local issuing organization. |
+| Renewal | Annual reaffirmation of LEI validity. |
+| Regulator reporting | MiFIR, derivatives reporting, etc. |
+
+## Modeling Assumptions
+
+- **LEI identifies legal entities only**, not natural persons or login accounts.
+- **Ownership is first-class** in LEI Level 2 (parent chains).
+- **Identity persistence is maintained by renewal**, not immutability of business facts.
+- **Public global directory** enables counterparty verification.
+- **LEI does not prove good behavior**; it proves identifiable legal presence.
+- **One LEI per legal entity** for global financial identification.
+
+## Identity-Canon Implications
+
+- LEI maps to **Identifier** 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**.
+- Renewal maps to **Lifecycle State** on Identifier/Commercial Record.
+- LEI exemplifies **commercial binding**: regulatory participation requires stable,
+  renewed legal identity.
+- Distinct from DUNS (credit/commerce) and from OIDC sub (authentication).
+
+## Terminology Conflicts
+
+- **Legal entity (LEI)** vs. **Legal Entity (canon)**: aligned when jurisdictionally recognized.
+- **Legal entity** vs. **Organization**: not every organization has LEI; LEI subset is regulated finance participants.
+- **LEI** vs. **company registration number**: national registry ID vs. global LEI.
+
+## Candidate Canonical Mappings
+
+| LEI concept | Candidate canonical concept |
+| --- | --- |
+| LEI code | Identifier (authoritative, global) |
+| Legal entity | Legal Entity / Organization |
+| Level 1 data | Commercial Record / registry Profile |
+| Level 2 parent | Ownership Relationship |
+| GLEIF registry | Evidence Source (authoritative) |
+| Annual renewal | Lifecycle State maintenance |
+| LOU issuance | Issuer Scope + Trust Relationship |
+
+## Open Questions
+
+- Should authoritative registry identifiers (LEI, company reg number) be a distinct
+  Identifier subtype with renewal semantics?
+
+## References
+
+- ISO 17442 — https://www.iso.org/standard/78829.html
+- GLEIF, Introducing the LEI — https://www.gleif.org/en/about-lei/introducing-the-legal-entity-identifier-lei
+- Wikipedia, Legal Entity Identifier — https://en.wikipedia.org/wiki/Legal_Entity_Identifier