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.EmulatedEntrypoint/Controllers/LeaderSkinController.cs

@@ -54,6 +54,7 @@ public class LeaderSkinController : SVSimController
         }
 
         var viewer = await _db.Viewers
+            .AsSplitQuery()
             .Include(v => v.Classes).ThenInclude(c => c.Class)
             .Include(v => v.Classes).ThenInclude(c => c.LeaderSkin)
             .Include(v => v.LeaderSkins)
@@ -115,6 +116,7 @@ public class LeaderSkinController : SVSimController
             .ToListAsync()).ToHashSet();
 
         var series = await _db.LeaderSkinShopSeries
+            .AsSplitQuery()
             .Where(s => s.IsEnabled)
             .Include(s => s.SetCompletionRewards)
             .Include(s => s.Products.Where(p => p.IsEnabled)).ThenInclude(p => p.Rewards)
@@ -274,6 +276,7 @@ public class LeaderSkinController : SVSimController
         if (!TryGetViewerId(out long viewerId)) return Unauthorized();
 
         var series = await _db.LeaderSkinShopSeries
+            .AsSplitQuery()
             .Include(s => s.SetCompletionRewards)
             .Include(s => s.Products.Where(p => p.IsEnabled))
             .FirstOrDefaultAsync(s => s.Id == request.SeriesId);

SVSim.EmulatedEntrypoint/Controllers/RankBattleController.cs

@@ -166,6 +166,39 @@ public sealed class RankBattleController : ControllerBase
 
         var r = await _resolver.ResolveAsync(mode, new BattlePlayer(vid, ctx), ct);
 
+        // Human-PvP path: stash battle context so the /finish handler can compose a
+        // ViewerBattleHistory row. Mirrors the ArenaTwoPick and AI-start hooks. Without
+        // this, /unlimited_rank_battle/finish and /rotation_rank_battle/finish always find
+        // a null context and BattleHistoryWriter no-ops (see live server_log 2026-07-02).
+        // Opponent identity is not yet plumbed through the resolver result (same gap as
+        // ArenaTwoPick — see its comment); zero placeholders until MatchContext carries the
+        // second player forward.
+        if (r.BattleId is not null && long.TryParse(r.BattleId, out var battleIdLong))
+        {
+            _battleContextStore.Set(vid, new BattleContext(
+                BattleId:           battleIdLong,
+                // Wire battle_type: 2 = rank battle (per docs/api-spec/common/types.ts.md
+                // #battle-types), same value the AI variant uses (mode is disambiguated
+                // by URL, not by battle_type).
+                BattleType:         2,
+                DeckFormat:         format.ToApi(),
+                TwoPickType:        0,
+                SelfClassId:        (int)ctx.ClassId,
+                SelfSubClassId:     0,
+                SelfCharaId:        int.TryParse(ctx.CharaId, out var ch) ? ch : 0,
+                SelfRotationId:     "0",
+                OpponentViewerId:   0,
+                OpponentName:       "",
+                OpponentClassId:    0,
+                OpponentSubClassId: 0,
+                OpponentCharaId:    0,
+                OpponentCountryCode: "",
+                OpponentEmblemId:   0,
+                OpponentDegreeId:   0,
+                OpponentRotationId: "0",
+                BattleStartTime:    DateTime.UtcNow));
+        }
+
         return Ok(new DoMatchingResponseDto
         {
             MatchingState = r.MatchingState,

SVSim.EmulatedEntrypoint/Controllers/SleeveController.cs

@@ -49,6 +49,7 @@ public class SleeveController : SVSimController
         var ownedSleeveIds = cosmeticsForInfo.SleeveIds.Select(id => (long)id).ToHashSet();
 
         var series = await _db.SleeveShopSeries
+            .AsSplitQuery()
             .Where(s => s.IsEnabled)
             .Include(s => s.Products.Where(p => p.IsEnabled)).ThenInclude(p => p.Rewards)
             .OrderBy(s => s.Id)