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.Database/Models/Config/SkipTutorialConfig.cs

@@ -0,0 +1,21 @@
+namespace SVSim.Database.Models.Config;
+
+/// <summary>
+/// When <see cref="Enabled"/>, fresh-signup viewers (via <c>/tool/signup</c> ->
+/// <see cref="SVSim.Database.Repositories.Viewer.ViewerRepository.RegisterAnonymousViewer"/>)
+/// are initialised at <c>MissionData.TutorialState = 100</c> — the post-tutorial baseline —
+/// instead of the prod default of <c>1</c> (TUTORIAL_STEP0). Intended for local dev / two-
+/// client PVP smoke where walking through the tutorial after every wiped identity is dead
+/// time. Off by default so prod-replicated captures still exercise the real tutorial flow.
+/// <para>
+/// This only affects the anonymous signup path. <see cref="SVSim.Database.Repositories.Viewer.ViewerRepository.RegisterViewer"/>
+/// (admin import + Steam-social) already lands at state 100 unconditionally.
+/// </para>
+/// </summary>
+[ConfigSection("SkipTutorial")]
+public class SkipTutorialConfig
+{
+    public bool Enabled { get; set; } = false;
+
+    public static SkipTutorialConfig ShippedDefaults() => new();
+}

SVSim.Database/Repositories/Pack/PackRepository.cs

@@ -10,6 +10,7 @@ public class PackRepository : IPackRepository
 
     public async Task<List<PackConfigEntry>> GetActivePacks(DateTime now) =>
         await _db.Packs
+            .AsSplitQuery()
             .Include(p => p.ChildGachas)
             .Include(p => p.Banners)
             .Where(p => p.IsEnabled && p.CommenceDate <= now && p.CompleteDate >= now)
@@ -23,6 +24,7 @@ public class PackRepository : IPackRepository
 
     public async Task<PackConfigEntry?> GetPack(int parentGachaId) =>
         await _db.Packs
+            .AsSplitQuery()
             .Include(p => p.ChildGachas)
             .Include(p => p.Banners)
             .FirstOrDefaultAsync(p => p.Id == parentGachaId);

SVSim.Database/Repositories/Story/StoryMasterRepository.cs

@@ -28,6 +28,7 @@ public class StoryMasterRepository : IStoryMasterRepository
 
     public Task<List<StoryChapter>> GetChaptersBySectionCharaAsync(int sectionId, int charaId)
         => _db.StoryChapters
+              .AsSplitQuery()
               .Include(c => c.BattleSettings).Include(c => c.Rewards).Include(c => c.SubChapters)
               .Where(c => c.SectionId == sectionId && c.CharaId == charaId)
               .ToListAsync();
@@ -46,6 +47,7 @@ public class StoryMasterRepository : IStoryMasterRepository
 
     public Task<StoryChapter?> GetChapterByIdAsync(int storyId)
         => _db.StoryChapters
+              .AsSplitQuery()
               .Include(c => c.BattleSettings).Include(c => c.Rewards).Include(c => c.SubChapters)
               .FirstOrDefaultAsync(c => c.StoryId == storyId);
 

SVSim.Database/Repositories/Viewer/ViewerRepository.cs

@@ -108,7 +108,12 @@ public class ViewerRepository : IViewerRepository
         // method used to pass) trips that check and silently bypasses the name-entry sub-step.
         // Empty string flows through /load/index → user_info.name → PlayerStaticData.UserName,
         // and the title screen surfaces the input dialog.
-        var viewer = await BuildDefaultViewer("");
+        //
+        // SkipTutorialConfig.Enabled: dev-mode fast path. When true, fresh signups land at
+        // state 100 (post-tutorial baseline) instead of TUTORIAL_STEP0 — cuts the walk-through-
+        // tutorial time after every wiped identity in the two-client PVP smoke. Off by default.
+        int initialTutorialState = _config.Get<SkipTutorialConfig>().Enabled ? 100 : 1;
+        var viewer = await BuildDefaultViewer("", initialTutorialState: initialTutorialState);
         viewer.Udid = udid;
         _dbContext.Set<Models.Viewer>().Add(viewer);