port(m1): wave 6c — Unity + Steam/FB/Adjust static-class shims (696->572)

Off-battle-path static surfaces (CS0103 cluster):
- UnityStatics: Gizmos, Physics2D, Caching, GUIUtility, Cursor, ColorUtility,
  ScreenCapture, RenderSettings, JsonUtility, Social + CursorLockMode enum.
- RaycastHit2D implicit-bool operator; ILocalUser in SocialPlatforms.
- Steamworks: Callback<T>.Create, AppId_t/CSteamID/HAuthTicket/SteamNetworkingIdentity,
  MicroTxn/GetAuthSessionTicket response structs, SteamAPI/User/Utils/Client statics.
  Removed empty dup GetAuthSessionTicketResponse_t from ThirdParty.cs.
- Facebook.Unity: FB + ILoginResult + FacebookDelegate<T>; com.adjust.sdk.Adjust;
  global TimeNativePlugin/Packsize native-plugin stubs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

SVSim.BattleEngine/Shim/External/SdkStubs.cs

@@ -79,6 +79,17 @@ namespace PlatformSupport.Collections.ObjectModel
     internal class _ShimAnchor { }
 }
 namespace Convention { internal class _ShimAnchor { } }
-namespace com.adjust.sdk { internal class _ShimAnchor { } }
+namespace com.adjust.sdk
+{
+    public static class Adjust
+    {
+        public static bool IsEditor() => true;
+        public static void addSessionCallbackParameter(string key, string value) { }
+    }
+}
 namespace BestHTTP.Decompression { internal class _ShimAnchor { } }
 namespace BestHTTP.SocketIO.Transports { internal class _ShimAnchor { } }
+
+// Native plugins (no decomp source) referenced unqualified from global scope.
+public static class TimeNativePlugin { public static float GetDeviceOperatingTime() => 0f; }
+public static class Packsize { public static void Test() { } }