Cross-exchange spread tick — ONE $0.02 call returns the live executable spread for a pair across Binance, Coinbase, Krak

Cross-exchange spread tick — ONE $0.02 call returns the live executable spread for a pair across Binance, Coinbase, Kraken, Bybit: best bid venue, best ask venue, spread in bps, and a deterministic TRADE / THIN / NONE verdict. Built for arbitrage monitoring loops; escalate to /api/crypto ($0.07) for the full CEX arbitrage read with fees and transfer paths. 30s freshness, no LLM in the path.