Along-route search endpoint (see module docs).

Places along the route, each with its honest engine-computed detour: {query, source, costing, route, max_detour_minutes, candidates: {considered, costed, cap}, results[]: {place, detour_minutes, detour_km, along_route_position, off_route_m}}, sorted by detour. When the geocode source browsed the first-party index by category (an explicit category, or a query that is entirely category phrases (fuel, petrol station, coffee near me), which promotes automatically), the response also carries matched_categories naming the normalised tokens browsed. With the fuel-price store configured (SN_FUEL_PRICES), fuel-station results also carry fuel_prices, fuel_brand and fuel_updated_at, and the response a fuel_attribution string