registry-manifest: 15 PublicSchema IRIs used by BReg and Relay fixtures are absent from the draft graph (#589 audit criterion)

## Context

#589 asked for a repository-wide audit of PublicSchema IRIs against the draft graph and was closed by PR #851. The review of that PR found the criterion may be unaddressed: 15 PublicSchema IRIs used by BReg and Relay fixtures are absent from the draft graph in `products/manifest`:

- CivilRegistration
- GroupRole and its five values
- Sex and its three values
- contact
- eventType
- local_identifier

## Acceptance

- Either the graph gains the terms the fixtures use, or the fixtures move to terms the graph defines, or the issue records why fixtures may use terms outside the graph.
- A check that fails when a fixture cites a PublicSchema IRI the graph does not define, so the audit does not drift again.

Commencez par inspecter le graphe préliminaire dans products/manifest ainsi que les fixtures BReg et Relay qui citent les IRI PublicSchema indiquées, puis examinez la PR #851 et l’issue #589 pour le contexte de l’audit. C’est terminé lorsque le graphe et les fixtures sont cohérents ou que l’exception est documentée, avec une vérification qui échoue lorsqu’un fixture cite une IRI PublicSchema non définie.

Rédigé par le modèle d'indexation à partir du texte de l'issue.