feat(battle-engine): UnityEngine member + static-class shims (3526->2706)

Extend the UnityEngine value/component shims with no-op members surfaced by the compile
loop (UnityWebRequest/Font/Mesh/LODGroup/AudioSource/Rigidbody/Camera/Sprite/Animation/
Transform/Material/Texture2D/Light/Input/Resources + CharacterInfo/Vector4), via partial
declarations + UnityShimExt.cs. Add the missing UnityEngine static classes (PlayerPrefs/
Physics/GUI/SystemInfo/Graphics/QualitySettings/StackTraceUtility) + enums (TextureFormat/
ColorSpace/EventModifiers/RenderTextureReadWrite) + Experimental.Rendering.GraphicsFormat*
in UnityStatics.cs. All cosmetic, off the battle path.

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

SVSim.BattleEngine/Shim/External/ThirdParty.cs

@@ -7,7 +7,7 @@ using System;
 // ---- remaining UnityEngine types ----
 namespace UnityEngine
 {
-    public class Font : Object { }
+    public partial class Font : Object { }
     public enum Space { World, Self }
     // NGUI's UIInputOnGUI reads Event.current (legacy IMGUI event).
     public class Event { public static Event current => null; }
@@ -15,7 +15,7 @@ namespace UnityEngine
 
 namespace UnityEngine.Networking
 {
-    public class UnityWebRequest : IDisposable { public void Dispose() { } }
+    public partial class UnityWebRequest : IDisposable { public void Dispose() { } }
 }
 
 // ---- CRI Atom/Mana audio+movie middleware: see External/CriShim.cs ----