Find best matches for a query in a candidate list

Finds the top matches for a query string within a list of candidates. Returns ranked matches with scores. Useful for entity resolution: 'which of these known entities does this input most likely refer to?' Tip: for organization or facility names, run /v1/names/org-name/clean on the inputs first so casing and punctuation don't depress scores. This is raw fuzzy string matching, not semantic — heavy abbreviations ('Univ' vs 'University', 'SLU') may still not match; lower the threshold or pre-expand abbreviations for those. Billing: 1 cost unit per query per started block of 1,000 candidates (e.g. 1 query x 300 candidates = 1 unit; 1 query x 2,500 candidates = 3 units). The response's meta.cost_units shows the exact charge.