curl -X POST https://api.aioka.io/v1/backtest \
  -H "X-API-Key: aik_pro_your_key_here" \
  -H "Content-Type: application/json" \
  -d '{"start_date": "2026-01-01", "end_date": "2026-04-01", "mode": "B"}'

{
  "total_trades": 8,
  "win_rate": 0.625,
  "total_pnl_usd": 312.50,
  "max_drawdown_pct": 4.2,
  "avg_hold_hours": 18.4,
  "period_days": 90,
  "mode": "B",
  "cached": false,
  "cache_ttl_seconds": 3600
}

{
  "detail": {
    "error": "period_too_long",
    "message": "Maximum backtest period is 90 days.",
    "requested_days": 365
  }
}