Find tickers by free-text `?search=` (name or symbol) across asset classes via `?market=stocks|crypto|fx|indices` (default stocks), with optional `?type=`, `?exchange=`, `?active=`, `?limit=`. Returns symbol, name, market, exchange, type, and identifiers. Use to discover crypto pairs (X:BTCUSD), FX pairs (C:EURUSD), and index symbols (I:SPX). From x402stock