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/AspectCamera.cs

@@ -3,74 +3,6 @@ using UnityEngine;
 [ExecuteInEditMode]
 public class AspectCamera : MonoBehaviour
 {
-	public Vector2 aspect = new Vector2(4f, 3f);
-
-	public Color32 backgroundColor = Color.black;
-
-	private float aspectRate;
-
-	private Camera _camera;
-
-	private static Camera _backgroundCamera;
-
-	private int sizeVal = 1;
-
-	public const float LOWER_LIMIT_ASPECT_RATIO = 0.5625f;
-
-	public const float UPPER_LIMIT_ASPECT_RATIO = 0.4618f;
-
-	public const float LOWER_LIMIT_ASPECT_RATIO_RECIPROCAL = 1.7777778f;
-
-	private const float SAFE_AREA_RATE = 0.892f;
-
-	private const float SAFE_AREA_NONE_RATE = 1f;
 
 	public static float SafeAreaRate;
-
-	private void Start()
-	{
-		aspectRate = aspect.x / aspect.y;
-		_camera = GetComponent<Camera>();
-		SafeAreaRate = 1f;
-		float num = (float)Screen.height / (float)Screen.width;
-		if (num < 0.5625f)
-		{
-			num = Mathf.Max(num, 0.4618f);
-			float t = (0.5625f - num) / 0.10069999f;
-			SafeAreaRate = Mathf.Lerp(1f, 0.892f, t);
-		}
-	}
-
-	private void UpdateScreenRate()
-	{
-		float num = aspect.y / aspect.x;
-		float num2 = (float)Screen.height / (float)Screen.width;
-		if (num2 < 0.5625f)
-		{
-			num2 = 0.5625f;
-		}
-		if (num > num2)
-		{
-			float num3 = num2 / num;
-			_camera.rect = new Rect(0f, 0f, 1f, 1f);
-			_camera.orthographicSize = (float)sizeVal * num3;
-		}
-		else
-		{
-			float num4 = num / num2;
-			_camera.rect = new Rect(0f, 0f, 1f, 1f);
-			_camera.orthographicSize = (float)sizeVal / num4;
-		}
-	}
-
-	private bool IsChangeAspect()
-	{
-		return _camera.aspect == aspectRate;
-	}
-
-	private void Update()
-	{
-		UpdateScreenRate();
-		_camera.ResetAspect();
-	}
 }