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/Public/VoxelDensityPrimitives.h

@@ -300,7 +300,6 @@ FORCEINLINE void VF_ApplyXYEdgeSealMC(float& Density, float WorldX, float WorldY
 // mathematical inner edge the helper is a true no-op, so claiming AllSolid there would be false.
 namespace VoxelDensityReach
 {
-    constexpr float SpineBlend        = 3.0f;
     constexpr float PassageBlend      = 4.0f;
     constexpr float EdgeProofMargin   = 1.0f;
 }