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/Cute/TimeUtil.cs

@@ -1,4 +1,8 @@
 using System;
+// TODO(engine-cleanup-pass2): 11 of 12 methods unrun in baseline
+//   Type: Cute.TimeUtil
+//   See data_dumps/reports/engine-cleanup/live-methods.baseline.txt
+
 
 namespace Cute;
 
@@ -70,21 +74,6 @@ public class TimeUtil
 
 	private static readonly DateTime UNIX_EPOCH = new DateTime(1970, 1, 1, 0, 0, 0, 0);
 
-	public const int DAY_HOUR = 24;
-
-	public const int DAY_SECOND = 86400;
-
-	public const int HOUR_SECOND = 3600;
-
-	public const int MINUTE_SECOND = 60;
-
-	public const int MILLI_SECOND = 1000;
-
-	public static DateTime GetNowTime(long serverTime, long connectClientTime)
-	{
-		return UNIX_EPOCH.AddSeconds((float)serverTime + TimeNativePlugin.GetDeviceOperatingTime() - (float)connectClientTime).ToLocalTime();
-	}
-
 	public static DateTime GetNowTime_UTC(long serverTime, long connectClientTime)
 	{
 		return UNIX_EPOCH.AddSeconds((float)serverTime + TimeNativePlugin.GetDeviceOperatingTime() - (float)connectClientTime);
@@ -95,53 +84,13 @@ public class TimeUtil
 		return UNIX_EPOCH.AddSeconds(TimeNativePlugin.GetDeviceOperatingTime());
 	}
 
-	public static long ToUnixTime(string str)
-	{
-		if (str == null)
-		{
-			return 0L;
-		}
-		return ToUnixTime(DateTime.Parse(str));
-	}
-
-	public static long ToUnixTime(DateTime dateTime)
-	{
-		return (long)ToUnixTimeDouble(dateTime);
-	}
-
-	public static double ToUnixTimeDouble(DateTime dateTime)
-	{
-		dateTime = dateTime.ToUniversalTime();
-		return (dateTime - UNIX_EPOCH).TotalSeconds;
-	}
-
-	public static DateTime FromUnixTime(long unixTime)
-	{
-		return UNIX_EPOCH.AddSeconds(Convert.ToDouble(unixTime)).ToLocalTime();
-	}
-
-	public static DateTime MicroTimeToFromUnixTime(long unixTime)
-	{
-		return FromUnixTime(unixTime / 1000);
-	}
-
 	public static TimeLeftParam GetTimeLeft(long nowTime, long endTime, long consumingTime = 0L)
 	{
 		return new TimeLeftParam(endTime - nowTime, consumingTime);
 	}
 
-	public static long GetElapsedTime(DateTime baseDateTime, DateTime dateTime)
-	{
-		return ToUnixTime(dateTime) - ToUnixTime(baseDateTime);
-	}
-
 	public static TimeSpan GetElapsedTimeByTimeSpan(DateTime baseDateTime, DateTime dateTime)
 	{
 		return baseDateTime - dateTime;
 	}
-
-	public static bool IsTermTime(string startDate, string endDate, long checkTime = 0L)
-	{
-		return true;
-	}
 }