Get a gear model's Reverb Price Guide detail

Returns one gear model's Reverb Price Guide detail: its specific finish/year variants, monthly average sale-price history, and a page of individual recent sales. slug is the model's slug, from reverb-price-guide-search's own models[].slug field. canonical_product_id optionally scopes to one specific variant from this model's own canonical_products[].id field (from a prior call without it); omitting it aggregates price history and recent sales across every variant, a broader, more heavily-sampled view. condition optionally scopes by Reverb's own Price Guide condition scale (listed below) -- a separate, 6-value enum from reverb-search's own listing condition field. range selects how far back the price history/recent-sales window looks. An unknown slug returns a typed not-found error.