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/NetworkBattleDefine.cs

@@ -32,12 +32,7 @@ public class NetworkBattleDefine
 	public enum NetworkBattleURI
 	{
 		None,
-		Resume,
 		Retry,
-		InitNetwork,
-		InitBattle,
-		InitRoomBattle,
-		Matched,
 		Loaded,
 		Deal,
 		Swap,
@@ -47,10 +42,8 @@ public class NetworkBattleDefine
 		TurnEnd,
 		TurnEndFinal,
 		PlayActions,
-		BattleStart,
 		BattleFinish,
 		ChatStamp,
-		Gungnir,
 		Echo,
 		Retire,
 		OppoDisconnect,
@@ -66,7 +59,6 @@ public class NetworkBattleDefine
 		JudgeResult,
 		Maintenance,
 		ReplayFinish,
-		Kill,
 		Watch
 	}
 
@@ -126,11 +118,9 @@ public class NetworkBattleDefine
 		spin,
 		resultCode,
 		isWin,
-		errorType,
 		pos,
 		self,
 		oppo,
-		battleStartDate,
 		time,
 		cards,
 		touch,
@@ -147,37 +137,7 @@ public class NetworkBattleDefine
 	public enum ReceiveNodeResultCode
 	{
 		None = 0,
-		Success = 1,
-		RoomStatusInfoError = 30101,
-		RoomCreateError = 30102,
-		RoomEntryError = 30103,
-		RoomKickError = 30104,
-		RoomLeaveError = 30105,
-		RoomReleaseError = 30106,
-		RoomForceReleaseError = 30107,
-		RoomReenterError = 30108,
-		RoomBattleReadeError = 30109,
-		RoomTournamentDeckError = 30110,
-		RoomTournamentError = 30111,
-		RoomSetupLock = 30112,
-		SwapTimeoutError = 31001,
-		MatchingTimeOut = 30201,
-		FoundRemovedUserErrorSelf = 32101,
-		FoundRemovedUserErrorOppo = 32102,
-		FoundRemovedUserErrorWatcher = 32103,
-		RoomTimeEndError = 32104,
-		WatcherInRemovedOwnerRoomError = 32105,
-		RoomTornamentOwnTimeEndError = 32106,
-		RoomTornamentOppoTimeEndError = 32107,
-		BattleFinishTimeEnd = 32108,
-		Different_UUID = 30001,
-		RedisReplyError = 30002,
-		WatchError = 30302,
-		CurrentBattleError = 30212,
-		UnexpectedPhaseError = 30213,
-		UnexistUserinfoError = 30003,
-		UnmatchedError = 30211
-	}
+		CurrentBattleError = 30212	}
 
 	public static readonly Dictionary<NetworkBattleURI, string> NetworkURINames;