Clarify ULAN predicate in unmodeled relationship example

[sundog358]

Summary

The existing unmodeled-relationship example describes Ferdinand Bol as a student of Rembrandt and recommends assigned_property when an appropriate predicate is known, but the generated example currently supplies only the display name.

This adds Getty's existing ulan1102_student_of predicate to that example. The direction matches the record: Ferdinand Bol is the subject carrying attributed_by, student of is the predicate, and Rembrandt is the assigned object. The full URI avoids requiring an additional compact-prefix declaration.

This is a narrow clarification of the existing pattern, not a proposal to add GVP properties to the Linked Art context.

Implementation evidence

Sun & Rain Works tested the same shape in Meta Museum using the canonical Linked Art context and its local Linked Art profile inspector. The public, self-contained fixture, verification evidence, and boundary notes are published here:

https://gist.github.com/sundog358/fe4602275bfff23eaf9503b6e597ca5a

Verification

• Clean checkout of v1.1 at fded7e715dcbe7642b6658151a616153dacf84a0
• Upstream dependencies installed in an isolated virtual environment
• python -m mkdocs build --clean passed
• Generated JSON-LD, HTML, and graph retain the full predicate URI
• Meta Museum focused conformance and documentation suite: 71 tests passed