feat(battle-engine): clear header frontier (Item/ErrorDialog/SDK shims + infra copies)

Resolves the 268-error header frontier: settings Item base, ErrorDialog.Data,
RoomConnectController nested types, Unity asset/light/collider types, CriWare/
CodeStage/Spine SDK surface, and copies INetworkLogger + SingletonMonoBehaviour
verbatim. Per F3 this unmasks the type bodies (~26.5k member-level errors now
visible) -- the real M1 bulk, attacked in following waves.

SVSim.BattleEngine/Engine/INetworkLogger.cs

@@ -0,0 +1,13 @@
+using System.Collections;
+using System.Collections.Generic;
+
+public interface INetworkLogger<out T> : IEnumerable<T>, IEnumerable
+{
+	void LogInfo(string text);
+
+	void LogWarning(string text);
+
+	void LogError(string text);
+
+	void ClearLog();
+}