Expose reusable Wikidata Q/P phrase mapping for meta-expression reasoning

[konard]

meta-expression issue: link-assistant/meta-expression#7

Context:
meta-expression needs human-language-style mapping from input phrases to Wikidata Q/P identifiers. In issue #7, Moon orbits the Sun now records Moon -> Q405, orbits -> P397, and Sun -> Q525, then uses a bounded P397 chain for evidence. This logic should eventually be shared rather than reimplemented in each project.

Proposal:

• Expose a reusable library API for phrase-to-Q/P mapping with context-aware disambiguation.
• Support caller-provided context hints such as astronomy, person, country/capital, or relation/property.
• Return ranked candidates with labels, descriptions, IDs, source URLs, and cache metadata.
• Keep browser-compatible caching so static apps can use it from workers.

Suggested consumer shape:

mapPhrasesToWikidata({
  phrases: ["Moon", "orbits", "Sun"],
  context: "astronomy",
});

This would let meta-expression reuse human-language disambiguation and linkable Q/P output directly.