Trading: shop kind and trade.open schema; trade test passes the RPG Plus prologue

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

locale/schema_es.properties

@@ -0,0 +1,11 @@
+trading/schema/builtin/trade_open = Abrir una tienda
+trading/schema/builtin/trade_open_desc = La ventana de comercio con el mercader
+trading/schema/field/shop = Tienda
+trading/schema/kind/shop = Tiendas
+trading/schema/kind/shop_desc = Lo que venden y compran los mercaderes
+trading/schema/field/name = Nombre
+trading/schema/field/currency = Moneda
+trading/schema/field/sells = Vende
+trading/schema/field/item = Objeto
+trading/schema/field/price = Precio
+trading/schema/field/buys = Compra