feat(battle-engine): close the AI-simulation subsystem (verbatim)

Copied the 89 uncopied AI*SimulationUtility/extension files defining the
AIVirtualCard/AIVirtualField extension methods; the compile loop then auto-closed
the revealed type deps (~3049 files total, drift-clean). 10.0k -> 62 errors.

SVSim.BattleEngine/Engine/IPaymentCallback.cs

@@ -0,0 +1,24 @@
+using System.Collections.Generic;
+
+public interface IPaymentCallback
+{
+	void evInitializeSucceeded();
+
+	void evInitializeFailed(string error);
+
+	void evPurchaseSucceeded(PaymentPurchase purchase);
+
+	void evPurchaseFailed(string error);
+
+	void evPurchaseCancelled(string error);
+
+	void evGetProductListSucceeded(List<PaymentSkuInfo> infos);
+
+	void evGetProductListFailed(string error);
+
+	void evConsumePurchaseSucceeded();
+
+	void evConsumePurchaseSucceedediOS();
+
+	void evConsumePurchaseFailed(string error);
+}