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/Skill_special_win.cs

@@ -5,15 +5,6 @@ using Wizard.Battle.View.Vfx;
 
 public class Skill_special_win : SkillBase
 {
-	private const int SHAKE_SCREEN_MAX_VALUE = 10;
-
-	private const float SHAKE_CAMERA_VECTOR_VALUE = 0.02f;
-
-	private const float SHAKE_CAMERA_TIME_COEFFICIENT = 0.05f;
-
-	private const float SHAKE_CAMERA_TIME_OFFSET = 0.2f;
-
-	private const string OPTION_WHEN_SPECIAL_LOSE = "when_special_lose";
 
 	public Skill_special_win(SkillParameter skillPrm, string option)
 		: base(skillPrm, option)
@@ -22,7 +13,7 @@ public class Skill_special_win : SkillBase
 
 	public override VfxWithLoading Start(CallParameter parameter)
 	{
-		if (BattleManagerBase.IsForecast)
+		if (base.SkillPrm.ownerCard.SelfBattlePlayer.BattleMgr.InstanceIsForecast)
 		{
 			return NullVfxWithLoading.GetInstance();
 		}
@@ -36,7 +27,7 @@ public class Skill_special_win : SkillBase
 			if (processInfo != null && !flag)
 			{
 				parameter.skillProcessor.Register(processInfo);
-				if (!BattleManagerBase.GetIns().IsRecovery)
+				if (!SkillPrm.ownerCard.SelfBattlePlayer.BattleMgr.IsRecovery)
 				{
 					BattleCardBase targetClass = targetCard.OpponentBattlePlayer.Class;
 					sequentialVfxPlayer.Register(SkillBase.CreateSingleVfx(base.SkillPrm.resourceMgr, () => targetClass.BattleCardView.GameObject.transform.position, new List<BattleCardBase> { targetClass }, targetClass.IsPlayer, targetClass.BattleCardView, "btl_nerva_2", EffectMgr.EngineType.SHURIKEN, "se_btl_nerva_2", EffectMgr.MoveType.DIRECT_LEADER, EffectMgr.TargetType.SINGLE, 0f));
@@ -64,12 +55,9 @@ public class Skill_special_win : SkillBase
 		return VfxWithLoading.Create(vfxWithLoading.LoadingVfx, mainVfx);
 	}
 
+	// Pre-Phase-5b: static camera-shake helper. Headless has no BattleCamera / BackGround view;
+	// the enclosing "special win" celebratory VFX is unreachable. Method body stubbed to no-op.
 	public static void ShakeScreen(int shakeScreenMinValue = 10)
 	{
-		BattleManagerBase ins = BattleManagerBase.GetIns();
-		float num = Mathf.Min(10, shakeScreenMinValue);
-		BattleCamera camera = ins.Camera;
-		ins.VfxMgr.RegisterImmediateVfx(SequentialVfxPlayer.Create(camera.ShakeCamera(Vector3.one * (num * 0.02f), num * 0.05f + 0.2f, 0f), WaitVfx.Create(num * 0.05f + 0.2f), camera.ShakeComplete()));
-		ins.BackGround.StartFieldShake();
 	}
 }