docs(mcp-access): add perps.previewHyperliquidOrderCost to gina-read reference

Author: ericjuta

docs/mcp-access/gina-read.mdx

@@ -56,6 +56,7 @@ These are the canonical catalog names. Your host may normalize punctuation or ad
 | `perps.fetchHyperliquidTrades`           | perps       |
 | `perps.fetchHyperliquidCandles`          | perps       |
 | `perps.fetchHyperliquidOrderBook`        | perps       |
+| `perps.previewHyperliquidOrderCost`      | perps       |
 | `perps.createHyperliquidTable`           | perps       |
 | `perps.executeSqlQuery`                  | perps       |
 | `predictions.searchPredictionMarkets`    | predictions |