feat(battle-engine): full Unity/VFX/god-object shims + expanded copy closure (2570 files)

Authored Unity primitive/object-model shim, VFX layer (control-flow-preserving, InstantVfx never invokes its action -- headless suppression), god-object stubs (GameMgr/EffectMgr/UIManager with faithfully-extracted nested enums), View/UI/Touch tree, LitJson+BetterList+Tuple copied, third-party stubs. Discovered Roslyn header-error masking: fixing class-header type errors unmasks body references, so the true copy closure is ~2570 files (was 782 under masking). Errors: masked-25720 -> 268; our shim files compile clean. Remaining: ~50 residual shim/external types, 24 NGUI UI-base overrides, static-type fixes, plus likely 1-2 more unmask waves.

SVSim.BattleEngine/Engine/BattleStageChoiceObject.cs

@@ -0,0 +1,36 @@
+using System;
+using UnityEngine;
+
+public class BattleStageChoiceObject : MonoBehaviour
+{
+	[SerializeField]
+	private UIButton _button;
+
+	[SerializeField]
+	private UITexture _texture;
+
+	[SerializeField]
+	private GameObject _offObject;
+
+	public Action _onButton;
+
+	public void Init()
+	{
+		UIEventListener.Get(_button.gameObject).onClick = null;
+		UIEventListener uIEventListener = UIEventListener.Get(_button.gameObject);
+		uIEventListener.onClick = (UIEventListener.VoidDelegate)Delegate.Combine(uIEventListener.onClick, (UIEventListener.VoidDelegate)delegate
+		{
+			_onButton();
+		});
+	}
+
+	public void SettingOffSelect(bool isOff)
+	{
+		_offObject.gameObject.SetActive(isOff);
+	}
+
+	public void SettingTexture(Texture texture)
+	{
+		_texture.mainTexture = texture;
+	}
+}