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/UIToggle.cs

@@ -33,14 +33,6 @@ public class UIToggle : UIWidgetContainer
 
 	public Validate validator;
 
-	[HideInInspector]
-	[SerializeField]
-	private UISprite checkSprite;
-
-	[HideInInspector]
-	[SerializeField]
-	private Animation checkAnimation;
-
 	[HideInInspector]
 	[SerializeField]
 	private GameObject eventReceiver;
@@ -49,10 +41,6 @@ public class UIToggle : UIWidgetContainer
 	[SerializeField]
 	private string functionName = "OnActivate";
 
-	[HideInInspector]
-	[SerializeField]
-	private bool startsChecked;
-
 	private bool mIsActive = true;
 
 	private bool mStarted;
@@ -80,108 +68,6 @@ public class UIToggle : UIWidgetContainer
 		}
 	}
 
-	public bool isColliderEnabled
-	{
-		get
-		{
-			Collider component = GetComponent<Collider>();
-			if (component != null)
-			{
-				return component.enabled;
-			}
-			Collider2D component2 = GetComponent<Collider2D>();
-			if (component2 != null)
-			{
-				return component2.enabled;
-			}
-			return false;
-		}
-	}
-
-	[Obsolete("Use 'value' instead")]
-	public bool isChecked
-	{
-		get
-		{
-			return value;
-		}
-		set
-		{
-			this.value = value;
-		}
-	}
-
-	public static UIToggle GetActiveToggle(int group)
-	{
-		for (int i = 0; i < list.size; i++)
-		{
-			UIToggle uIToggle = list[i];
-			if (uIToggle != null && uIToggle.group == group && uIToggle.mIsActive)
-			{
-				return uIToggle;
-			}
-		}
-		return null;
-	}
-
-	private void OnEnable()
-	{
-		list.Add(this);
-	}
-
-	private void OnDisable()
-	{
-		list.Remove(this);
-	}
-
-	private void Start()
-	{
-		if (startsChecked)
-		{
-			startsChecked = false;
-			startsActive = true;
-		}
-		if (!Application.isPlaying)
-		{
-			if (checkSprite != null && activeSprite == null)
-			{
-				activeSprite = checkSprite;
-				checkSprite = null;
-			}
-			if (checkAnimation != null && activeAnimation == null)
-			{
-				activeAnimation = checkAnimation;
-				checkAnimation = null;
-			}
-			if (Application.isPlaying && activeSprite != null)
-			{
-				activeSprite.alpha = (startsActive ? 1f : 0f);
-			}
-			if (EventDelegate.IsValid(onChange))
-			{
-				eventReceiver = null;
-				functionName = null;
-			}
-		}
-		else
-		{
-			mIsActive = !startsActive;
-			mStarted = true;
-			bool flag = instantTween;
-			instantTween = true;
-			Set(startsActive);
-			instantTween = flag;
-		}
-	}
-
-	private void OnClick()
-	{
-		if (base.enabled && isColliderEnabled && UICamera.currentTouchID != -2)
-		{
-			value = !value;
-		}
-	}
-
 	public void Set(bool state)
 	{
 		if (validator != null && !validator(state))