v0.4.0 — dual NCIt anchoring

Dual NCIt anchoring (decision D4): every NCIt reference — skos:exactMatch and usdm:boundCodelist — now carries both the EVS identifier and the resolvable OBO PURL, so HTML anchor links resolve again (the EVS host ncicb.nci.nih.gov no longer exists in DNS, though NCI Thesaurus 26.05d still declares the namespace; the EVS form is kept as identifier).
8,641 triples (+441 vs v0.3.1: 396 exactMatch + 45 boundCodelist twins). Structural counts unchanged: 86 classes, 693 properties, 57 codelist bindings.

Note for consumers: usdm:boundCodelist is multi-valued from this release — filter by namespace prefix when joining on a single form. Rationale and evidence in docs/iri-and-governance.md, decision D4.

v0.1.0 — model + codelist bindings

First tagged release. Mechanical Turtle/RDF rendering of CDISC USDM v4
from cdisc-org/DDF-RA@v4.0.0.

Model (from dataStructure.yml):

• 86 named owl:Class (84 NCIt-anchored via skos:exactMatch)
• 693 properties (359 datatype + 334 object), 312 NCIt-anchored
• Inheritance, cardinality (owl:Restriction), Value/Ref distinction,
  Model Name and Model Representation as annotation properties
• Polymorphic associations rendered as owl:unionOf ranges

Codelist bindings (from USDM_CT.xlsx, sheet 1):

• 57 declaring-class bindings on Code-typed property IRIs
• 45 with structured C-codes; 12 free-text references to external
  dictionaries (ISO 3166, ISO 639, MedDRA, SNOMEDCT, FHIR, ...)
  preserved verbatim via usdm:boundCodelistNote

Pipeline: three notebooks (fetch → generate → validate) + four
example notebooks demonstrating model navigation, binding inventory,
coverage-gap analysis, and permitted-term resolution via NCI EVS.

Out of scope for v0.1, deliberate (see docs/known-gaps.md):
SULO/upper-ontology alignment, sheet-2 enumerated codelist value
binding, alignment to CDISC Library RDF, SHACL shapes, multi-format
publication.