wip(assembler): round L31 -- FI recipe column audit corrected; recipe-stamped audit runner

On the real FloatingIslands recipe, column caps sit inside anchor-island rock and native bedrock;
the old check sampled the route foot. The audit now samples each planned cap against the native
field (negative control: a cap moved into air is detected). The audit runner records requested vs
actual recipe and exits on mismatch. All 16 passage rows (4 styles x 2 recipes x 2 compilers) pass.
The readable shader uses a smooth tint. Interim: FI Gradient displacement capped at width/256
(flat floor, no contour rings); restoring real undulation is L32. Evaluator 19.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CSFYgsdW8ejZSyiMf4qRSX

Standalone/Core/include/VoxelForgeCore/VoxelForgeCore.h

@@ -249,8 +249,10 @@ namespace VoxelForgeCore
     // L'assembleur v1 encode coordonnees et scalaires en 1/256 de voxel, independamment des tuiles.
     inline constexpr std::int64_t WorldAssemblySubvoxelsPerVoxel = 256;
     inline constexpr std::uint32_t WorldAssemblySchemaVersion = 2;
-    // Version 14 adds shared passage columns; version 16 smooths owner Gradient faces.
-    inline constexpr std::uint32_t WorldAssemblyEvaluatorVersion = 16;
+    // Version 14 adds shared passage columns; version 16 smooths owner Gradient faces;
+    // version 18 limits FloatingIslands Gradient face displacement to one voxel;
+    // version 19 reduces it to one quarter voxel to remove the residual floor contour.
+    inline constexpr std::uint32_t WorldAssemblyEvaluatorVersion = 19;
 
     enum class FieldChannel : std::uint32_t
     {

Standalone/Core/src/ResolvedLayoutInternal.h

@@ -359,7 +359,10 @@ ResolvedLayoutTransitionBandsV1 EvaluateResolvedLayoutTransitionBandsV1(
         return result;
     }
 
-    const std::int64_t displacement = (noise * (width / 8)) / TransitionQ16;
+    // FloatingIslands floor faces retain the same deterministic Gradient field but
+    // cap displacement at one quarter voxel so the transition does not read as a contour.
+    const std::int64_t gradientDivisor=upper.generatorKind=="FloatingIslands"?256:8;
+    const std::int64_t displacement = (noise * (width / gradientDivisor)) / TransitionQ16;
     const std::int64_t interfaceZ = seam + displacement;
     result.upperBedrockBottomMicrometres = interfaceZ;
     result.upperBedrockTopMicrometres = interfaceZ + upperThickness;

Standalone/Core/src/ShapeWorldInternal.h

@@ -269,7 +269,8 @@ public:
         const VoxelForgeCore::ResolvedLayoutStratumV2& Lower) const
     {
         const std::int64_t width=std::max<std::int64_t>(0,Upper.transitionWidthMicrometres);
-        if(Upper.transitionMode=="Gradient")return width/8;
+        if(Upper.transitionMode=="Gradient")
+            return width/(Upper.generatorKind=="FloatingIslands"?256:8);
         if(Upper.transitionMode!="Interleaved")return 0;
         const std::int64_t upperThickness=std::max<std::int64_t>(0,
             Upper.bedrock.topMicrometres-Upper.bedrock.bottomMicrometres);