Complete IDENTITY-WP-0003 corpus backfill and model refinement

Backfill all 23 research source notes with terminology extracts, modeling
assumptions, conflicts, canonical mappings, and references. Refresh terminology
artifacts, refine the conceptual model with explicit scenario paths, reconcile
canon surfaces and open questions, and mark the workplan finished.

research/social-community-graphs/schema-org-person-organization-membership.md

@@ -1,50 +1,112 @@
-# Schema Org Person Organization Membership
+# Schema.org Person Organization Membership
 
 ## Source Type
 
-TODO: Identify whether this is a standard, specification, product documentation, academic concept, architecture pattern, or implementation reference.
+Semantic vocabulary. Schema.org types and properties for Person, Organization,
+membership, and role-like affiliations.
 
 ## Domain
 
-TODO: Classify the source domain.
+Structured data about people and organizations, SEO/social graphs, and
+membership representation on the web.
 
 ## Why This Source Matters
 
-Schema.org Person, Organization, memberOf, affiliation, and public entity metadata.
+Schema.org distinguishes persons, organizations, membership, employee roles,
+and affiliation properties — widely used for web-scale person/org modeling.
 
 ## Key Concepts
 
-TODO:
-- concept 1
-- concept 2
-- concept 3
+- **Person**: living human; properties include `name`, `email`, `identifier`,
+  `sameAs`, `affiliation`, `worksFor`, `memberOf`.
+- **Organization**: business, club, or other collective; `member`, `employee`,
+  `department`, `subOrganization`, `parentOrganization`.
+- **OrganizationRole**: intermediate type linking person to organization with
+  `roleName`, `startDate`, `endDate`.
+- **member / memberOf**: reciprocal membership between Person and Organization.
+- **employee / worksFor**: employment relationship properties.
+- **affiliation**: organization a person is affiliated with (looser than member).
+- **sameAs**: URL of related entity — often used for weak equivalence/synonymity.
+- **identifier**: PropertyValue or Text for external IDs.
+- **SportsTeam / PerformingGroup**: specialized Organization subtypes.
+- **ProgramMembership**: membership in a program with tier/benefits.
 
 ## Relevant Terminology
 
-TODO: Extract terms used by the source and note their source-specific meaning.
+| Term | Source meaning |
+| --- | --- |
+| Person | Human being in structured data. |
+| Organization | Collective entity (company, club, NGO). |
+| memberOf | Person belongs to Organization. |
+| member | Organization has Person as member. |
+| employee | Person employed by Organization. |
+| worksFor | Inverse employment link. |
+| affiliation | Looser org association for Person. |
+| sameAs | Related/equivalent resource URL (weak linking). |
+| OrganizationRole | Named role with temporal bounds. |
+| subOrganization | Org hierarchy child. |
+| identifier | External ID for entity. |
 
 ## Modeling Assumptions
 
-TODO: Capture assumptions made by the source about users, accounts, organizations, tenants, groups, roles, identities, relationships, or credentials.
+- **Person means human** in schema.org intent.
+- **Membership and employment are properties**, not reified relationship objects
+  (except OrganizationRole).
+- **sameAs is informal equivalence** between web resources, not verified identity.
+- **Organizations can nest** via subOrganization/parentOrganization.
+- **Roles can be typed** via OrganizationRole with dates.
+- **No authentication or authorization** semantics.
+- **Properties are multi-valued**; one person can have many memberships.
 
 ## Identity-Canon Implications
 
-TODO: Explain what this source suggests for the canonical identity model.
+- Schema.org **Person** maps to **Natural Person**.
+- **Organization** maps to **Organization** collective actor.
+- **memberOf / member** map to **Membership Relationship**.
+- **employee / worksFor** map to **Affiliation Relationship** or employment
+  specialization of Membership.
+- **affiliation** maps to **Affiliation Relationship** (looser).
+- **OrganizationRole** maps to **Role** relationship with temporal bounds.
+- **subOrganization** maps to structural relationship between Organization
+  actors (child/parent).
+- **sameAs** maps to **weak Synonymity Assertion** between web resources —
+  high conflation risk if treated as strong link.
+- **identifier** maps to **Identifier** PropertyValue.
+- Supports S03 (sub-orgs), S07 (informal groups as Organization subtypes), S08.
 
 ## Terminology Conflicts
 
-TODO: Record where this source uses terms differently from other sources.
+- **Person vs. Profile**: schema.org Person is often used for public profile page.
+- **member vs. employee**: overlapping employment semantics; not always distinct.
+- **sameAs vs. Synonymity**: sameAs is SEO linking, not identity proofing.
+- **Organization vs. Community**: SportsTeam/PerformingGroup blur social vs. org.
+- **Role vs. OrganizationRole**: roleName may be job title or permission label.
 
 ## Candidate Canonical Mappings
 
-TODO: Map source-specific concepts to identity-canon candidate concepts.
+| Schema.org concept | Candidate canonical concept |
+| --- | --- |
+| Person | Natural Person |
+| Organization | Organization |
+| memberOf / member | Membership Relationship |
+| employee / worksFor | Affiliation or employment Membership |
+| affiliation | Affiliation Relationship |
+| OrganizationRole | Role + Membership with temporal bounds |
+| subOrganization | Organization hierarchy Relationship |
+| sameAs | Weak Synonymity Assertion (caution) |
+| identifier | Identifier |
+| ProgramMembership | Membership Relationship (program scope) |
 
 ## Open Questions
 
-TODO:
-- Question 1
-- Question 2
+- Should sameAs ever promote beyond weak Synonymity without additional evidence?
+- Does OrganizationRole warrant a canonical temporal Relationship subtype?
+- How should ProgramMembership map vs. Community membership?
+- Should subOrganization be a distinct Relationship type or Organization attribute?
 
 ## References
 
-TODO: Add canonical URLs, RFC/spec identifiers, documentation links, and citation notes.
+- Schema.org Person — https://schema.org/Person
+- Schema.org Organization — https://schema.org/Organization
+- Schema.org OrganizationRole — https://schema.org/OrganizationRole
+- Schema.org sameAs — https://schema.org/sameAs