wip(unreal): round 3 -- owner's in-game defects classified; opening room fixed; Core biome query

Luna, integration round 3, from the owner's four in-game screenshots:
- Capsule rings at the opening and the shaft continuing through the cave room were Core
  world defects: the synthetic bore is removed and the opening gets a finite origin room
  and floor (solid below). New world version, W1/W8/W16 identical: density
  a8bcb72d41092503, mesh 90f29ba15e24579f, payload 82c6b489e7bb7fd7, topology
  7b99448a1f844f2c.
- B-side landing and surface: headless coverage found no missing tiles or LOD-transition
  gaps (960 / 640 fine tiles compiled after travel); best explained by Core's missing
  SurfaceWorld representation. Null-RHI cannot rule out a presentation-only issue.
- Core mode GetBiomeAtWorldLocation now answers (e.g. Biome_Surface_Plain); biome
  terrain itself is not generated yet (proposal: native Core SurfaceWorld evaluator).
Owner checked the Step29 viewer himself: the surface strate type is absent there too.

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

Source/VoxelForge/Private/VoxelWorld.cpp

@@ -12463,16 +12463,12 @@ int32 AVoxelWorld::GetStrateAtPosition(FVector WorldPosition) const
 FVoxelBiomeQuery AVoxelWorld::GetBiomeAtWorldLocation(FVector WorldLocation) const
 {
     FVoxelBiomeQuery Out;
-    if (bUseVoxelForgeCore)
-    {
-        // Core ne publie pas encore le query biome historique.
-        // Core does not expose the legacy biome query API yet.
-        return Out;
-    }
     if (!Generator) return Out;
 
     // Bring the world point into actor-LOCAL voxel space — the SAME transform the decoration scatter
     // applies (UpdateDecorations), so the probe agrees with where props actually land.
+    // Convert using the legacy generator's authored voxel size; Core still queries this biome field.
+    // Convertir avec l'échelle historique du générateur; Core interroge toujours ce champ de biomes.
     const FVector Local = GetActorTransform().InverseTransformPosition(WorldLocation);
     const float VX = Local.X / VOXEL_SIZE;
     const float VY = Local.Y / VOXEL_SIZE;