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/PlayHandCardReflection.cs

@@ -18,11 +18,6 @@ public class PlayHandCardReflection : ReceivePlayActionsReflectionBase
 		_networkBattleData = networkBattleData;
 	}
 
-	public void SetOperateMgr(OperateMgr operateMgr)
-	{
-		_operateMgr = operateMgr;
-	}
-
 	public void ReadySetting(int cardIndex, List<NetworkBattleReceiver.TargetData> targetDataList)
 	{
 		_cardIdx = cardIndex;
@@ -108,16 +103,15 @@ public class PlayHandCardReflection : ReceivePlayActionsReflectionBase
 		List<BattleCardBase> list = null;
 		list = ((!player.IsPlayer) ? NetworkBattleGenericTool.GetOpposingCardObjTarget(_battleMgr, _playHandTargetDataList) : NetworkBattleGenericTool.LookForActionDataToTargetCard(_battleMgr, _playHandTargetDataList));
 		ParallelVfxPlayer parallelVfxPlayer = ParallelVfxPlayer.Create();
-		if ((GameMgr.GetIns().IsWatchBattle && player.IsPlayer) || GameMgr.GetIns().IsAdminWatch)
+		if ((_battleMgr.GameMgr.IsWatchBattle && player.IsPlayer) || _battleMgr.GameMgr.IsAdminWatch)
 		{
-			CanNotTouchCardVfx canNotTouchCardVfx = new CanNotTouchCardVfx();
+			VfxBase canNotTouchCardVfx = NullVfx.GetInstance();
 			_battleMgr.VfxMgr.RegisterImmediateVfx(canNotTouchCardVfx);
 			parallelVfxPlayer.Register(_actingCard.SelfBattlePlayer.BattleView.RemoveFusionSelectedCardFromHand(_selectedCards));
 			parallelVfxPlayer.Register(_actingCard.SelfBattlePlayer.BattleView.CreateStopShowSelectVfx(_actingCard, isAct: true, stopChoiceSelectUiImmediately: false));
 			parallelVfxPlayer.Register(_operateMgr.FusionCard(indexToCardBase, player.IsPlayer, list));
 			_battleMgr.VfxMgr.RegisterSequentialVfx(SequentialVfxPlayer.Create(parallelVfxPlayer, InstantVfx.Create(delegate
 			{
-				canNotTouchCardVfx.End();
 			})));
 		}
 		else
@@ -132,19 +126,19 @@ public class PlayHandCardReflection : ReceivePlayActionsReflectionBase
 	public void ChoiceBraveMove(BattlePlayerBase player, List<int> choiceIdList)
 	{
 		BattleCardBase battleCardBase = player.Class;
-		if (!player.CanChoiceBraveThisTurn && !BattleManagerBase.GetIns().IsRecovery)
+		if (!player.CanChoiceBraveThisTurn && !_battleMgr.IsRecovery)
 		{
 			SendEcho(battleCardBase, _networkBattleData.GetReceiveData().actionType);
 			return;
 		}
 		ParallelVfxPlayer parallelVfxPlayer = ParallelVfxPlayer.Create();
-		GameMgr gameMgr = GameMgr.GetIns();
+		GameMgr gameMgr = _battleMgr.GameMgr;
 		if ((!gameMgr.IsWatchBattle || !player.IsPlayer) && !gameMgr.IsAdminWatch && !_battleMgr.IsRecovery)
 		{
 			parallelVfxPlayer.Register(InstantVfx.Create(delegate
 			{
 				gameMgr.GetEffectMgr().Start(EffectMgr.EffectType.CMN_CARD_SELECT_3, _battleMgr.BattleUIContainer.EnemyChoiceBraveBtn.position);
-				gameMgr.GetSoundMgr().PlaySe(Se.TYPE.SYS_CMN_CARD_SELECT_3);
+
 				player.BattleView.UpdateChoiceBraveButtonPulsateEffectAndSprite();
 			}));
 		}