[UI] Review RDF 1.2 feature support

RDF 1.2 has not yet been published as a W3C Recommendation, and its adoption is currently limited. Patterns and best practices may still evolve.

This issue serves as a reminder for the UI Task Force to review the current status and usage of RDF 1.2 features, such as triple terms, and to consider whether these features should be promoted, demoted, or otherwise represented in the UI documentation.