Find the closest match to a colour from each archive independently.

Accepts ONE of: hex value, colour name, or free-text query. Returns n_per_archive results from each available archive side by side.

Useful for:

• "How does the China archive describe this blue vs the Pigment archive?"
• "What pigment name matches this British heritage colour?"
• "Show me how all three archives see #2030A0"

Examples: {"hex": "#2030A0", "n_per_archive": 2} {"name": "Jingtai Blue", "n_per_archive": 3} {"query": "the colour of autumn wheat fields", "n_per_archive": 2}