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_ko.properties

@@ -0,0 +1,11 @@
+trading/schema/builtin/trade_open = 상점 열기
+trading/schema/builtin/trade_open_desc = 그 상인과의 거래 창
+trading/schema/field/shop = 상점
+trading/schema/kind/shop = 상점
+trading/schema/kind/shop_desc = 상인이 팔고 사는 것
+trading/schema/field/name = 이름
+trading/schema/field/currency = 화폐
+trading/schema/field/sells = 판매
+trading/schema/field/item = 아이템
+trading/schema/field/price = 가격
+trading/schema/field/buys = 구매