Match Markets Batch

Batch-resolve many markets by exact Kalshi ticker and/or Polymarket slug in one request.

The single-market /match endpoint costs one round-trip per identifier, so resolving thousands of mappings serially is slow. This endpoint takes lists of tickers and/or slugs (send them together in one call) and returns a full market row — including river_id, ticker, slug and exchange_name — for every identifier that matched. Identifiers with no match come back in unmatched_tickers / unmatched_slugs.