refactor(dead-code): remove functions, members and types with no caller

Each symbol below had zero references in Source/ (tests included), Tools/,
Config/ and the build files after comment/string stripping.

Functions: EvaluateTunnelCoreSDF, EvaluateSDF (uncached wrapper),
IsTunnelSupportFloorWorldPoint, BuildTunnelSupportFloorColumn,
IsTunnelSupportFloorColumnZ, GetTunnelSupportFloorColumnBand,
VF_TunnelFloorAtSegment, VF_ProjectSweptTunnelFloor, FVoxelWormField
EvaluateExact, ApplyPassageLandingAirMC, ApplyPassageTunnelAirMC,
GetGenerationParamsFingerprint, FVoxelStrateCorpus::LoadFromSettings,
GetSkippedDefinitions, VF_RollStrateParams, VF_ArePlayerFitConnectedWithSampler,
VF_GetVoxelSeasonSelectionReasonName, UVoxelSeasonAsset::GetManifestContentHash,
FVoxelStackSampler::IsRunning, CompareSkippedPostValue,
MakeSurfaceColumnSource, WriteObjTile, ExploreEffectName,
ExploreTileClassName, and the VoxelTypes.h chunk-local helpers
(WorldToLocalCoord, ChunkToWorldPos, LocalToIndex, IndexToLocal,
IsValidLocalCoord, GetFaceDirection, GetFaceNormal, CHUNK_SIZE_SQUARED,
CHUNK_VOLUME).

Members/types: write-only floor flags (FVoxelOpSample::
bProtectedStructuralFloor, StructuralFloorMinimumDensity,
bTunnelCoreSupportFloor; bSupportFloor on the tunnel evaluations;
FTunnelFloorSegmentProfile::NumSteps), UVoxelStrateManager::BlendChunks,
unused FSummary counters in the stack sampler, two unused
FVoxelSeasonCompositionSettings aliases, and a few unused locals/constants.

No UPROPERTY, UFUNCTION, reflected type or enum was touched. Behaviour is
unchanged: removed code was unreachable or only written, never read.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01URDGLsu7c4nunqNFPJEFPU

Source/VoxelForge/Private/VoxelStackSampler.cpp

@@ -863,12 +863,6 @@ void FVoxelStackSampler::Shutdown()
     StopAndWrite();
 }
 
-bool FVoxelStackSampler::IsRunning() const
-{
-    FScopeLock LifecycleLock(&LifecycleMutex);
-    return Impl != nullptr;
-}
-
 bool FVoxelStackSampler::RegisterCurrentThread(int32 LODLevel)
 {
     // Keep this as the first and only operation in the disabled fast path.  In particular, do not