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/Wizard/MyPageBGInfo.cs

@@ -0,0 +1,31 @@
+using System.Collections.Generic;
+using LitJson;
+
+namespace Wizard;
+
+public class MyPageBGInfo
+{
+	public MyPageDetail.BGType BGType { get; set; }
+
+	public string Id { get; set; }
+
+	public List<string> RandomIdList { get; set; }
+
+	public MyPageBGInfo()
+	{
+	}
+
+	public MyPageBGInfo(JsonData json)
+	{
+		BGType = (MyPageDetail.BGType)json["select_type"].ToInt();
+		Id = json["mypage_id"].ToString();
+		RandomIdList = new List<string>();
+		if (json.TryGetValue("mypage_id_list", out var value))
+		{
+			for (int i = 0; i < value.Count; i++)
+			{
+				RandomIdList.Add(value[i].ToString());
+			}
+		}
+	}
+}