Method LogPurchase
LogPurchase(Product, string, int)
Under MOCALIB_USE_COST_CENTER, logs an iap_sdk event with price, currency,
product ID, and gameplay context. Firebase auto-tracks the standard purchase event via Unity IAP;
this method adds the COST_CENTER-specific extended fields only.
public static void LogPurchase(Product product, string playMode = "", int level = 0)