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/Wizard/ArenaCommonLobby.cs

@@ -33,26 +33,6 @@ public class ArenaCommonLobby : MonoBehaviour
 	[SerializeField]
 	private UILabel _decisionButtonLabel;
 
-	private const ResourcesManager.AssetLoadPathType CHARA_TEXTURE_TYPE = ResourcesManager.AssetLoadPathType.ClassCharaBase;
-
-	private const iTween.EaseType MOVE_EASE_TYPE = iTween.EaseType.easeOutExpo;
-
-	private const float CHARA_MOVE_DIST = 4.6875f;
-
-	private const float CHARA_MOVE_TIME = 0.5f;
-
-	private const float MAIN_OBJECT_MOVE_DIST = 2.8125f;
-
-	private const float MAIN_OBJECT_MOVE_TIME = 0.5f;
-
-	private const float MAIN_OBJECT_MOVE_DELAY = 0.2f;
-
-	private const float BUTTON_MOVE_DIST = 1.5625f;
-
-	private const float BUTTON_MOVE_TIME = 0.5f;
-
-	private const float BUTTON_MOVE_DELAY = 0.5f;
-
 	private List<string> _unloadAssetList = new List<string>();
 
 	private GameObject _decisionButtonEffect;
@@ -102,8 +82,7 @@ public class ArenaCommonLobby : MonoBehaviour
 		List<string> loadAssetList = new List<string>();
 		List<Action> loadEndCallbackList = new List<Action>();
 		ResourcesManager resMgr = Toolbox.ResourcesManager;
-		string strSkinId = GameMgr.GetIns().GetDataMgr().GetCharaPrmByClassId(initParam.ClassId)
-			.skin_id.ToString();
+		string strSkinId = "0"; // Pre-Phase-5b: no chara master headless
 		loadAssetList.Add(resMgr.GetAssetTypePath(strSkinId, ResourcesManager.AssetLoadPathType.ClassCharaBase));
 		loadAssetList.Add(resMgr.GetAssetTypePath("cmn_ui_btn_1", ResourcesManager.AssetLoadPathType.Effect2D));
 		ArenaCommonLobbyLoadRequest arenaCommonLobbyLoadRequest = _battleInfo.Init(initParam, _unloadAssetList);
@@ -151,7 +130,7 @@ public class ArenaCommonLobby : MonoBehaviour
 		{
 			yield return null;
 		}
-		GameMgr.GetIns().GetSoundMgr().PlaySe(Se.TYPE.SYS_WINDOW_MOVE);
+
 		iTween.MoveTo(_charaTexture.gameObject, iTween.Hash("position", _charaInitPos, "time", 0.5f, "islocal", false, "easetype", iTween.EaseType.easeOutExpo));
 		iTween.MoveTo(_mainObjectRoot, iTween.Hash("position", _mainObjectInitPos, "time", 0.5f, "delay", 0.2f, "islocal", false, "easetype", iTween.EaseType.easeOutExpo));
 		iTween.MoveTo(_decisionButton.gameObject, iTween.Hash("position", _buttonInitPos, "time", 0.5f, "delay", 0.5f, "islocal", false, "easetype", iTween.EaseType.easeOutExpo));