Return the cached PromotionClass from GET_PROMOTION_CLASS

Character load and the promotion trainer re-read static_rune_promotion on every
call and replaced the cached object. They now get the object loaded at boot,
as GET_BASE_CLASS already does; the DB query is only a miss fallback.
No value changes: the cached and re-read objects hold the same row.

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

src/engine/db/handlers/dbPromotionClassHandler.java

@@ -50,7 +50,15 @@ public class dbPromotionClassHandler extends dbHandlerBase {
 
     public PromotionClass GET_PROMOTION_CLASS(final int objectUUID) {
 
-        PromotionClass promotionClass = null;
+        PromotionClass promotionClass;
+
+        if (objectUUID == 0)
+            return null;
+
+        promotionClass = (PromotionClass) DbManager.getFromCache(mbEnums.GameObjectType.PromotionClass, objectUUID);
+
+        if (promotionClass != null)
+            return promotionClass;
 
         try (Connection connection = DbManager.getConnection();
              PreparedStatement preparedStatement = connection.prepareStatement("SELECT * FROM `static_rune_promotion` WHERE `ID` = ?")) {