build: VoxelForge compiles in Unreal 5.7 on Linux (L65); Linux-only Unreal trace timing fields

Linux UE builds failed on the Core wrapper module: the Linux-only PerModuleInline.gen.cpp saw Standalone/Compat
shadow headers instead of the engine's, and WITH_EDITOR was redefined under -Werror. Compat headers now forward
to the engine headers with include_next for generated Linux module TUs (canonical Core TUs opt into the Compat
definitions via CoreNamespacePreamble.h); CoreMinimal.h undefines WITH_EDITOR first. VoxelForgeCore.Build.cs
enables that forwarding and AVX2 on Linux only; VoxelForge.Build.cs disables Unity on Linux only. Portability:
std::int64_t consistently in VoxelContentManager.cpp; grouped &&/|| in VoxelRedefinedDensityField.cpp. Linux-only
trace fields split Core generateTile / mesh copy / RMC stream build. Standalone Clang and GCC whole-view hashes
are unchanged vs 3202193. The Unreal spawn trace is blocked by the owner's new assets (SW route sweep fails).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

Source/VoxelForgeCore/VoxelForgeCore.Build.cs

@@ -39,6 +39,13 @@ public class VoxelForgeCore : ModuleRules
 
 		PublicDependencyModuleNames.Add("Core");
 		CppStandard = CppStandardVersion.Cpp20;
+		if (Target.Platform == UnrealTargetPlatform.Linux)
+		{
+			// The compatibility include directory contains Unreal-shaped placeholders. On Linux,
+			// let generated module TUs pass those names through to UE while Core shims opt in.
+			PrivateDefinitions.Add("VFCORE_COMPAT_FORWARD_HEADERS=1");
+			MinCpuArchX64 = MinimumCpuArchitectureX64.AVX2;
+		}
 		// Canonical Standalone code predates UE's stricter warning defaults; keep this narrow to legal local shadowing.
 		CppCompileWarningSettings.ShadowVariableWarningLevel = WarningLevel.Off;
 		FPSemantics = FPSemanticsMode.Precise;