fix(unreal): U1 -- Unreal compiles again on L61; CoreGeometry asset section; versioned layout-unit upgrade

Windows MSVC catch-up after abyss L15-L61 (no Unreal there): 64-bit clipmap
shift (C4334), qualified VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel, UHT
metadata and duplicate-signature fixes. Optional CoreGeometry section on
UVoxelStrateDefinition (native caves, lattice, profiled heightfields, named
stamps, rooms/tunnels; off/empty by default), resolved after passage planning.
VoxelForgeAssetVersion 2 converts strate height/transition/gap to metres on
load (exact, 0 m change on the owner's 5 assets; packages never saved).
Gates pass (SurfaceWorld, FloatingIslands, Core-off, M2, W1/W8/W16).
KNOWN REGRESSION vs L14 (2026-10-20, same command, same PC): full set 3.9 ->
5.37 s, worker-seconds 15.8 -> 30, LOD0 1.11 -> 1.69 s, ring 0.50 -> 0.80 s;
not yet attributed (Core L15-L61 vs Unreal side).
Report: Standalone/Research/WorldAssemblerM3/Unreal1.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Source/VoxelForge/Private/VoxelWorld.cpp

@@ -7567,6 +7567,14 @@ bool AVoxelWorld::GetVoxelForgeCoreWorldAssembly(
     return bUseVoxelForgeCore && !OutCanonicalJson.IsEmpty() && !OutContentHash.IsEmpty();
 }
 
+bool AVoxelWorld::GetVoxelForgeCoreResolvedLayout(
+    FString& OutCanonicalJson, FString& OutStableIdentity) const
+{
+    OutCanonicalJson = VoxelForgeCoreResolvedLayoutJson;
+    OutStableIdentity = VoxelForgeCoreResolvedLayoutIdentity;
+    return bUseVoxelForgeCore && !OutCanonicalJson.IsEmpty() && !OutStableIdentity.IsEmpty();
+}
+
 bool AVoxelWorld::QueryVoxelForgeCoreDensityAt(FVector WorldLocation, float& OutDensity) const
 {
     OutDensity = 0.0f;
@@ -7585,6 +7593,8 @@ bool AVoxelWorld::InitializeVoxelForgeCoreWorld(FString& OutFailureReason)
     OutFailureReason.Reset();
     VoxelForgeCoreWorldAssemblyJson.Reset();
     VoxelForgeCoreWorldAssemblyHash.Reset();
+    VoxelForgeCoreResolvedLayoutJson.Reset();
+    VoxelForgeCoreResolvedLayoutIdentity.Reset();
     if (!bUseVoxelForgeCore) return true;
     if (!Settings || !StrateManager)
     {
@@ -7617,6 +7627,17 @@ bool AVoxelWorld::InitializeVoxelForgeCoreWorld(FString& OutFailureReason)
         UE_LOG(LogTemp, Error, TEXT("[VoxelForgeCoreRuntime] %s"), *OutFailureReason);
         return false;
     }
+    if (const VoxelForgeCore::ResolvedLayoutSnapshotV3* ResolvedLayout = Snapshot->resolvedLayout())
+    {
+        const std::string CanonicalLayout = ResolvedLayout->ToJson();
+        if (CanonicalLayout.empty())
+        {
+            OutFailureReason = TEXT("the resolved Core layout could not be serialized canonically.");
+            return false;
+        }
+        VoxelForgeCoreResolvedLayoutJson = UTF8_TO_TCHAR(CanonicalLayout.c_str());
+        VoxelForgeCoreResolvedLayoutIdentity = UTF8_TO_TCHAR(ResolvedLayout->stableIdentity.c_str());
+    }
     if (const VoxelForgeCore::WorldAssemblyManifest* Assembly = Snapshot->worldAssembly())
     {
         const std::string CanonicalAssembly = Assembly->ToJson();
@@ -7793,6 +7814,8 @@ void AVoxelWorld::FallBackToLegacyAfterCoreInitializationFailure(const FString&
     }
     VoxelForgeCoreWorldAssemblyJson.Reset();
     VoxelForgeCoreWorldAssemblyHash.Reset();
+    VoxelForgeCoreResolvedLayoutJson.Reset();
+    VoxelForgeCoreResolvedLayoutIdentity.Reset();
     bUseVoxelForgeCore = false;
     // The Core adapter sets this before validation; legacy generation must not inherit it.
     // L'adaptateur Core l'active avant validation ; le générateur historique ne doit pas en hériter.
@@ -15117,6 +15140,7 @@ FString AVoxelWorld::GetCurrentSeasonContentHash() const
     }
 
     FString AssemblyHash = VoxelForgeCoreWorldAssemblyHash;
+    FString ResolvedLayoutIdentity = VoxelForgeCoreResolvedLayoutIdentity;
     if (AssemblyHash.IsEmpty())
     {
         FString AssemblyJson;
@@ -15153,12 +15177,17 @@ FString AVoxelWorld::GetCurrentSeasonContentHash() const
                 AssemblyHash = FString::Printf(TEXT("%016llx"),
                     static_cast<unsigned long long>(Assembly->contentHash));
             }
+            if (const VoxelForgeCore::ResolvedLayoutSnapshotV3* ResolvedLayout = Snapshot->resolvedLayout())
+            {
+                ResolvedLayoutIdentity = UTF8_TO_TCHAR(ResolvedLayout->stableIdentity.c_str());
+            }
         }
     }
     const bool bHybridMesher = CoreMesherRecipe != EVoxelForgeCoreMesherRecipe::MarchingCubesV1;
     const uint32 CoreVoxelSizeMicrons = static_cast<uint32>(
         FMath::RoundToInt(GetActiveVoxelSizeCm() * 10000.0f));
-    if (AssemblyHash.IsEmpty() && !bHybridMesher && CoreVoxelSizeMicrons == 250000)
+    if (AssemblyHash.IsEmpty() && ResolvedLayoutIdentity.IsEmpty()
+        && !bHybridMesher && CoreVoxelSizeMicrons == 250000)
     {
         return SeasonHash;
     }
@@ -15183,6 +15212,11 @@ FString AVoxelWorld::GetCurrentSeasonContentHash() const
         Payload += TEXT("|world_assembly=");
         Payload += AssemblyHash;
     }
+    if (!ResolvedLayoutIdentity.IsEmpty())
+    {
+        Payload += TEXT("|resolved_layout=");
+        Payload += ResolvedLayoutIdentity;
+    }
     if (CoreVoxelSizeMicrons != 250000)
     {
         Payload += FString::Printf(TEXT("|core_voxel_size_microns=%u"), CoreVoxelSizeMicrons);