engine cleanup passes 4-7 + multi-instancing ambient rip

Squashes 146 commits from battle-engine-extraction. Net: 2,045 files changed,
+11,896 / -158,687 lines. Ships engine passes 4-7 (dead-code cull, view-layer
stub, receive-path shrink) plus the Phase-5 AsyncLocal ambient deletion that
turns concurrent battles into a type-system property rather than a scope
contract.

## What landed

**Passes 4-7 (chunks 1-34):** Extended the Phase-4 const-false collapse into a
cascading cull across the skill graph, view layer, and receive-path periphery.
Six mode flags (IsWatchBattle/IsReplayBattle/IsAdmin/IsAdminWatch/IsPuzzleQuest/
IsAINetwork) became `const false`, every guarded block deleted. Field*.cs
subclass ctors + BackGroundBase + ObjectChecker culled to no-ops. Mulligan
family reworked to take a mgr param through IMulliganMgr.InitMulligan.
Emotion/Recovery/Resource clusters null-stubbed. Prediction/OperationSimulator/
skill filters converted from static ambient reads to per-mgr reads via
SkillPrm.ownerCard.SelfBattlePlayer.BattleMgr / ins.BattleMgr / this.BattleMgr.

**Phase-5 ambient rip (chunks 35-47):** Deleted BattleAmbient / BattleAmbient-
Context / TestBattleScope in full. Every per-battle mutable slot now lives on
the mgr instance itself:
  mgr.InstanceIsForecast / InstanceIsRandomDraw / InstanceRecoveryInfo /
  InstanceViewerId / InstanceNetworkAgent / GameMgr
BattleManagerBase.GetIns() returns null unconditionally; the residual static
flags + 3 façades (Certification.ViewerId, Data.BattleRecoveryInfo,
ToolboxGame.RealTimeNetworkAgent) are null-tolerant defaults kept for the
handful of engine-internal readers that still reference their types. Zero
BattleAmbient references anywhere in engine + node + tests.

Added pre-seeded GameMgr ctor overload threaded through the mgr chain
(BattleManagerBase → SingleBattleMgr / NetworkBattleManagerBase → NetworkStandard-
BattleMgr → HeadlessBattleMgr / HeadlessNetworkBattleMgr). Fixtures build a
GameMgr, seed it via HeadlessEngineEnv.SeedCharaIds/SeedNetUser, and pass it
to the mgr's ctor — no ambient reach.

Node side (SVSim.BattleNode/SessionBattleEngine): _ctx replaced with a plain
GameMgr field; 34 `using var _ambient = BattleAmbient.Enter(_ctx)` scope wraps
ripped from every accessor and mutator; EngineGlobalInit.WirePerSessionGameMgr
takes GameMgr as a param and runs from SessionBattleEngine.SetupInternal
BEFORE mgr construction.

Test side: TestBattleScope deleted; 18 fixture [SetUp]s migrated to
`HeadlessEngineEnv.EnsureProcessGlobals()`; MultiInstanceEngineTests rewritten
around per-mgr construction (GetIns() → null is the pinned invariant).

## Regression fixes

- **chunk-48** (MulliganCtrl): chunk-35's `= null` stubs on card lookups broke
  the live receive-driven Deal path (BattlePlayerBase.DrawCard NRE'd downstream
  of NetworkPlayerMulliganCtrl.StartMulliganVfx). Restored the three lookups
  via `_battlePlayer.BattleMgr.GetBattleCardIdx`. Engine tests were satisfied
  by the WireMulliganPhase seam; unit tests exposed the live-path gap.

## Ship state

- SVSim.BattleEngine.Tests: 56/56 pass, 2 skip
- SVSim.UnitTests: 1554/1554 pass (was 1523/31-fail before chunk 48)
- Solution build: 0 source warnings (40 pre-existing NU1902 MessagePack CVEs
  in SVSim.EmulatedEntrypoint, unrelated)
- Sequential PVP smoke: verified live (two back-to-back battles, no regression
  on cleanup/spinup)
- Concurrent PVP smoke: verified live

Adds tools/engine-port/ClosureAnalyzer/ — the Roslyn transitive-type-closure
analyzer needed to make future cascade cleanup safe (per feedback memory
"Engine cleanup needs closure tool" from the 2026-06-28 pass-3 failure).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.BattleEngine/Engine/ClassSkinPurchasePage.cs

@@ -16,8 +16,6 @@ public class ClassSkinPurchasePage : BaseShopPurchasePage
 		rewardOnly
 	}
 
-	private const int DEFAULT_INDEX = 0;
-
 	[SerializeField]
 	private UITable _uiTableProducts;
 
@@ -27,8 +25,8 @@ public class ClassSkinPurchasePage : BaseShopPurchasePage
 	[SerializeField]
 	private PurchaseConfirm _PrefabDialogPurchaseConfirm;
 
-	[SerializeField]
-	private ClassSkinDetailWindow _PrefabDialogSkinDetail;
+	// ClassSkinDetailWindow removed (DEAD-COLD engine cleanup Task 13)
+	// private ClassSkinDetailWindow _PrefabDialogSkinDetail;
 
 	[SerializeField]
 	private ShopDrumrollScrollManager _drumrollManager;
@@ -49,8 +47,6 @@ public class ClassSkinPurchasePage : BaseShopPurchasePage
 
 	private DialogBase _dialogSelectBuyMeans;
 
-	private DialogBase _dialogProductDetail;
-
 	private DialogBase _dialogCrystalShortage;
 
 	private bool _isBuyConnect;
@@ -103,7 +99,7 @@ public class ClassSkinPurchasePage : BaseShopPurchasePage
 	{
 		if (_loadedVoiceList.Count > 0)
 		{
-			GameMgr.GetIns().GetSoundMgr().StopVoiceAll(0f);
+
 			Toolbox.ResourcesManager.RemoveAssetGroup(_loadedVoiceList);
 			_loadedVoiceList.Clear();
 		}
@@ -374,28 +370,12 @@ public class ClassSkinPurchasePage : BaseShopPurchasePage
 
 	private void _onTapClassSkinImage(ClassSkinPlate plate, bool isMulti)
 	{
-		if (!(_dialogProductDetail != null))
-		{
-			_dialogProductDetail = UIManager.GetInstance().CreateDialogClose();
-			_dialogProductDetail.SetSize(DialogBase.Size.M);
-			_dialogProductDetail.SetTitleLabel(Data.SystemText.Get("Dia_BuySkin_003_Title"));
-			_dialogProductDetail.SetButtonLayout(DialogBase.ButtonLayout.CloseBtn);
-			ClassSkinDetailWindow component = UnityEngine.Object.Instantiate(_PrefabDialogSkinDetail).GetComponent<ClassSkinDetailWindow>();
-			_dialogProductDetail.SetObj(component.gameObject);
-			if (isMulti)
-			{
-				component.SetMultiData(plate.SeriesInfo);
-			}
-			else
-			{
-				component.SetSingleData(plate.ProductInfo, _loadedVoiceList);
-			}
-		}
+		// ClassSkinDetailWindow removed (DEAD-COLD engine cleanup Task 13)
 	}
 
 	private void onPushBuyButton(ClassSkinPlate plate, bool isMulti)
 	{
-		GameMgr.GetIns().GetSoundMgr().PlaySe(Se.TYPE.SYS_BTN_DECIDE);
+
 		_selectPlate = plate;
 		if (isMulti)
 		{
@@ -578,9 +558,11 @@ public class ClassSkinPurchasePage : BaseShopPurchasePage
 		{
 			DialogBase diaChange = UIManager.GetInstance().CreateDialogClose();
 			int skinId = _purchaseProductInfo.leader_skin_id;
-			ClassCharacterMasterData charaData = GameMgr.GetIns().GetDataMgr().GetCharaPrmBySkinId(skinId);
+			// Pre-Phase-5b: pulled ClassCharacterMasterData via GetCharaPrmBySkinId + GetClanNameByKey.
+			// Headless has no chara master; leave the purchase-success dialog text as the base
+			// "purchased X" substitution without the class/chara suffix.
+			ClassCharacterMasterData charaData = null;
 			string text = Data.SystemText.Get("Shop_0022", _purchaseProductName.Replace("\n", ""));
-			text = text + "\n\n" + Data.SystemText.Get("Shop_0108", GameMgr.GetIns().GetDataMgr().GetClanNameByKey(charaData.class_id), charaData.chara_name);
 			diaChange.SetText(text);
 			diaChange.SetTitleLabel(Data.SystemText.Get("Dia_BuySkin_004_Title"));
 			diaChange.SetButtonLayout(DialogBase.ButtonLayout.BlueBtn_CancelBtn);