standalone: VoxelForgeCore link-safe next to Unreal -- internals in vfcore::detail, symbol check

- The copied generator, mesher and Compat stand-ins compile inside vfcore::detail.
- CheckCoreSymbols.ps1 (run by Build.ps1) fails on any unqualified Unreal-style symbol in the
  library: 16,255 on 557f6aa, 0 now. A UE 5.7 CoreMinimal.h + VoxelForgeCore.h smoke compile passes.
- Output identical: 11 hash rows at W1/W8, routes 5642/5642, look/passage/far audits pass,
  bad-shell control fails, six captures byte-identical.
Cost, measured by me interleaved (8 workers, cold, 4 runs each, first run excluded): 0.963 s vs
0.937 s for 557f6aa, ~27 ms in shape compilation; same math, so codegen/inlining. To be found.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ

Standalone/Core/src/CoreNamespacePreamble.h

@@ -0,0 +1,54 @@
+#pragma once
+
+// Every standard or platform header used by the copied implementation must be included before
+// its wrapper opens vfcore::detail. This prevents system declarations from being nested in the
+// private namespace when the implementation includes its Unreal-shaped compatibility headers.
+#include <algorithm>
+#include <array>
+#include <atomic>
+#include <bit>
+#include <cassert>
+#include <cctype>
+#include <charconv>
+#include <chrono>
+#include <cmath>
+#include <condition_variable>
+#include <cstdarg>
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <filesystem>
+#include <fstream>
+#include <functional>
+#include <immintrin.h>
+#include <initializer_list>
+#include <iomanip>
+#include <iostream>
+#include <limits>
+#include <map>
+#include <math.h>
+#include <memory>
+#include <memory_resource>
+#include <mutex>
+#include <new>
+#include <numeric>
+#include <optional>
+#include <shared_mutex>
+#include <span>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <string_view>
+#include <thread>
+#include <type_traits>
+#include <unordered_map>
+#include <unordered_set>
+#include <utility>
+#include <variant>
+#include <vector>
+
+// VFJson is a small, stateless standalone input parser with no Unreal-shaped names. Keeping its
+// value tree shared lets the viewer resolve its reference world and Core snapshot from one parse.
+#include "Json.h"

Standalone/Core/src/StandaloneSnapshotAdapter.h

@@ -1,12 +1,15 @@
 #pragma once
 
-#include "OwnerWorldLoader.h"
+#include "Json.h"
 #include "VoxelForgeCore/VoxelForgeCore.h"
 
-#include <memory>
+#include <string>
 
 namespace VoxelForgeCore
 {
-    // Private standalone adapter: keeps the compatibility holders behind the public value API.
-    ResolvedWorldSnapshot MakeStandaloneSnapshot(std::shared_ptr<FStandaloneOwnerWorld> owner);
+    // Standalone-only bridge. Core parses into its namespaced compatibility snapshot and applies
+    // the same command-line overrides as the viewer's reference loader.
+    ResolvedWorldSnapshot MakeStandaloneSnapshotFromParsedJson(const VFJson::Value& jsonRoot,
+        std::int32_t seed,std::int32_t clipRadius,std::int32_t maxLodOverride,
+        bool roundTunnels,bool enhancedTunnelWalls,std::string& error);
 }

Standalone/Core/src/VoxelForgeCore.cpp

@@ -1,20 +1,18 @@
+#include "CoreNamespacePreamble.h"
 #include "StandaloneSnapshotAdapter.h"
+#include "VoxelForgeCore/VoxelForgeCore.h"
 
+namespace vfcore::detail
+{
 #include "FarShellsInternal.h"
 #include "VoxelClipmapDesiredTiles.h"
 #include "VoxelMarchingCubesMesher.h"
-#include "VoxelForgeCore/VoxelForgeCore.h"
-
-#include <algorithm>
-#include <bit>
-#include <cmath>
-#include <cstring>
-#include <map>
-#include <numeric>
-#include <stdexcept>
+}
 
 namespace VoxelForgeCore
 {
+    using namespace ::vfcore::detail;
+
     struct ResolvedWorldSnapshot::Data
     {
         std::shared_ptr<FStandaloneOwnerWorld> owner;
@@ -185,8 +183,36 @@ namespace VoxelForgeCore
         }
     };
 
-    ResolvedWorldSnapshot MakeStandaloneSnapshot(std::shared_ptr<FStandaloneOwnerWorld> owner)
-    { return detail_StandaloneSnapshotAdapter::FromOwner(std::move(owner)); }
+    ResolvedWorldSnapshot MakeStandaloneSnapshotFromParsedJson(const VFJson::Value& jsonRoot,
+        std::int32_t seed,std::int32_t clipRadius,std::int32_t maxLodOverride,
+        bool roundTunnels,bool enhancedTunnelWalls,std::string& error)
+    {
+        auto owner=std::make_shared<FStandaloneOwnerWorld>();
+        if(!StandaloneOwnerLoader::Resolve(jsonRoot,*owner,error))return {};
+
+        const bool seedChanged=owner->Seed!=seed;
+        owner->Settings->Seed=seed;
+        owner->Seed=seed;
+        owner->ClipRadius=clipRadius;
+        owner->Settings->ClipRadius=clipRadius;
+        if(seedChanged)
+        {
+            owner->Manager=std::make_unique<UVoxelStrateManager>();
+            if(!owner->Manager->Initialize(owner->Settings.get(),seed))
+            {error="standalone copied strate manager failed while applying viewer settings";return {};}
+            owner->Generator=std::make_unique<UVoxelGenerator>();
+            owner->Generator->InitializeSettings(owner->Settings.get());
+            owner->Generator->SetStrateManager(owner->Manager.get());
+        }
+        owner->Generator->bStandaloneResearchRoundTunnels=roundTunnels;
+        owner->Generator->bStandaloneResearchEnhancedWalls=enhancedTunnelWalls;
+        if(maxLodOverride>=0)
+        {
+            owner->MaxClipLevel=maxLodOverride;
+            owner->Settings->MaxClipLevel=maxLodOverride;
+        }
+        return detail_StandaloneSnapshotAdapter::FromOwner(std::move(owner));
+    }
 
     std::optional<ResolvedWorldSnapshot> ResolvedWorldSnapshot::FromJson(
         std::string_view json,std::string& error)