wip(assembler): round S1 -- one Core voxel-size source; per-tile feature lists (islands)

AVoxelWorld::CoreVoxelSizeCm (default 25, 32 voxels/tile) flows through plan, field,
mesher, content, water, atmosphere, edits and collision. Staged-owner BuildHost passes at
20 cm (SurfaceWorld + islands, W1/W8/W16, anchors, BP edits, collision) with a fixed-25cm
negative control; default-size hashes match round 4; Core off stays legacy 12.5 cm.
Reusable BuildWorldAssemblyFeatureTileListV1; wired into FloatingIslands only so far.
256-island stress: tile p95 112.5 -> 2.0 ms, 0 mismatches, dropped-feature control fails.
Content placement measured (no populated cells): island ground search 7.25 ms/cell vs
legacy 0.29 ms -- open. Outside-review evaluation in Round5/REPORT.md.

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

Source/VoxelForge/Public/VoxelWorld.h

@@ -284,6 +284,12 @@ public:
     UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Voxel World|Core", meta = (DisplayName = "Core Mesher Recipe"))
     EVoxelForgeCoreMesherRecipe CoreMesherRecipe = EVoxelForgeCoreMesherRecipe::MarchingCubesV1;
 
+    /** Physical Core voxel size in centimeters. Tile coordinates remain 32 voxels per tile.
+     *  Taille physique d'un voxel Core en centimetres; chaque tuile contient 32 voxels. */
+    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Voxel World|Core",
+        meta = (DisplayName = "Core Voxel Size (cm)", ClampMin = "12.5", ClampMax = "25.0"))
+    float CoreVoxelSizeCm = 25.0f;
+
     /** Core-only clipmap radius, in level-0 Core tiles. Does not read Settings->ClipRadius. */
     UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Voxel World|Core", meta = (ClampMin = "1", ClampMax = "64"))
     int32 CoreClipRadius = 3;
@@ -440,10 +446,10 @@ public:
      * Applies a spherical brush that subtracts density.
      *
      * @param Position - World-space center of the carve brush
-     * @param Radius - Brush radius in legacy Runtime voxels (12.5 cm); Core converts it to
-     *                 25 cm voxels to preserve the physical brush size.
-     * @param Strength - Legacy Runtime density offset; Core scales it to 25 cm units.
-     *                   Offset de densite Runtime historique; Core le convertit en unite de 25 cm.
+     * @param Radius - Brush radius in legacy Runtime voxels; Core converts it using its configured
+     *                 voxel size to preserve the physical brush size.
+     * @param Strength - Legacy Runtime density offset; Core scales it to its configured size.
+     *                   Offset de densite Runtime historique; Core le convertit selon sa resolution.
      */
     UFUNCTION(BlueprintCallable, Category = "Voxel World|Modification")
     void CarveAtPosition(FVector Position, float Radius = 6.0f, float Strength = 10.0f);
@@ -453,19 +459,19 @@ public:
      * Applies a spherical brush that adds density.
      *
      * @param Position - World-space center of the fill brush
-     * @param Radius - Brush radius in legacy Runtime voxels (12.5 cm); Core converts it to
-     *                 25 cm voxels to preserve the physical brush size.
-     * @param Strength - Legacy Runtime density offset; Core scales it to 25 cm units.
-     *                   Offset de densite Runtime historique; Core le convertit en unite de 25 cm.
+     * @param Radius - Brush radius in legacy Runtime voxels; Core converts it using its configured
+     *                 voxel size to preserve the physical brush size.
+     * @param Strength - Legacy Runtime density offset; Core scales it to its configured size.
+     *                   Offset de densite Runtime historique; Core le convertit selon sa resolution.
      */
     UFUNCTION(BlueprintCallable, Category = "Voxel World|Modification")
     void FillAtPosition(FVector Position, float Radius = 6.0f, float Strength = 10.0f);
 
     /**
      * Box brush carve/fill. Position is world-space (Unreal units); ExtentVoxels is the
-     * box half-size in legacy Runtime voxels (12.5 cm). Core converts it to 25 cm voxels.
-     * Strength is a legacy-voxel density offset; Core scales it to 25 cm units and forces its sign.
-     * La force est un decalage de densite historique; Core la convertit en unite de 25 cm et impose le signe.
+     * box half-size in legacy Runtime voxels. Core converts it using its configured voxel size.
+     * Strength is a legacy-voxel density offset; Core scales it and forces its sign.
+     * La force est un decalage de densite historique; Core la convertit selon sa resolution et impose le signe.
      */
     UFUNCTION(BlueprintCallable, Category = "Voxel World|Modification")
     void CarveBox(FVector Position, FVector ExtentVoxels, float Strength = 12.0f);
@@ -475,8 +481,8 @@ public:
 
     /**
      * Capsule brush carve/fill between two world-space points (Unreal units). Tube radius and density offset
-     * use legacy Runtime voxels (12.5 cm); Core converts both to 25 cm units.
-     * Creuse/remplit une capsule entre deux points monde. Rayon et decalage Runtime historique sont convertis en unite Core de 25 cm.
+     * use legacy Runtime voxels; Core converts both using its configured voxel size.
+     * Creuse/remplit une capsule entre deux points monde; rayon et decalage historiques suivent la resolution Core.
      * Great for boring tunnels or laying solid pillars/walls.
      */
     UFUNCTION(BlueprintCallable, Category = "Voxel World|Modification")
@@ -487,7 +493,7 @@ public:
 
     /**
      * Apply a fully-specified modification (any shape). Centers/endpoints and brush dimensions
-     * are expected in active voxel coordinates here (12.5 cm legacy, 25 cm Core); high-level
+     * are expected in active voxel coordinates here (legacy or configured Core size); high-level
      * helpers convert legacy brush sizes to preserve physical dimensions.
      * Returns nothing; re-meshes affected chunks.
      */
@@ -593,7 +599,7 @@ public:
     UFUNCTION(BlueprintPure, Category = "Voxel World|Strate")
     int32 GetStrateAtPosition(FVector WorldPosition) const;
 
-    // Convert actor-local physical Z to/from UVoxelStrateManager's legacy 12.5 cm space.
+    // Convert actor-local physical Z to/from UVoxelStrateManager's legacy coordinate space.
     // Convertit Z local physique vers/depuis l'espace historique de UVoxelStrateManager.
     float ToStrateManagerLocalZ(float LocalZCm) const;
     float FromStrateManagerLocalZ(float ManagerLocalZCm) const;