Clarify terminology for selective disclosure to avoid confusion

The current Selective Disclosure section within the specification uses terminology that already has a well established meaning in the Verifiable Credentials ecosystem, where selective disclosure typically refers to cryptographic techniques used in verifiable presentations.

The approach described in this specification is different. It relies on role-based access control, Identity Resolver routing, and multiple credential variants rather than cryptographic selective disclosure within a single credential. This distinction is consistent with how confidentiality and access control are described elsewhere in the UNTP specification, particularly in the Decentralised Access Control and Architecture sections.

Using the term selective disclosure in this context may cause confusion for implementers familiar with VC standards and could introduce friction. Perhaps adding a short note, for example: "This specification does not describe cryptographic selective disclosure via verifiable presentations. Instead, it defines a variant-based approach where different actors have access to different complete credentials."

Alternatively, the terminology could be updated to something like Variant-based Disclosure or Selective Redaction.