wip(assembler): round L29 -- strate transitions honoured at the bedrock/ceiling interface

EVoxelStrateTransition from the upper strate shapes the bedrock(N)/ceiling(N+1) interface in the
shared composition layer: Hard flat; Gradient = smooth 2D hash surface (16 m owner width, about 4 m
measured undulation); Interleaved = 3D domain-warped fingered overlap within the width. Each band
keeps >= 2 Core voxels solid; faces return to the seam near passage mouths. Interface audit over
512 m: 0 hole columns for all modes; wider-than-declared and too-thin controls rejected. All passage,
route, proof and validator audits pass; deterministic Clang = GCC. Evaluator 15. Cost +4% SW,
+1.3% FI vs L28. Open: ring-like artifact on the FI floor capture; transition look unverified.

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

Standalone/Source/StreamBenchmarkPipeline.h

@@ -240,6 +240,172 @@ namespace StandaloneStreamBenchmark
         return Hash;
     }
 
+    inline bool AuditResolvedStrateTransitions(const VoxelForgeCore::World& Field,
+        const FStandaloneOwnerWorld& Owner,
+        const VoxelForgeCore::ResolvedLayoutSnapshotV3& Layout)
+    {
+        constexpr std::int64_t XYExtentMicrometres=256000000;
+        constexpr std::int64_t XYStepMicrometres=8000000;
+        const std::int64_t coreMicrometres=std::max<std::uint32_t>(1,Owner.CoreVoxelSizeMicrons);
+        const std::int64_t zStepMicrometres=std::max<std::int64_t>(1,coreMicrometres/2);
+        const std::int64_t minimumBandMicrometres=2*coreMicrometres;
+        std::uint64_t interfacesPassed=0,totalColumns=0,passageColumnsSkipped=0;
+        std::uint64_t holeColumns=0,airSamples=0,solidSamples=0;
+        bool negativeWidthRejected=false,negativeThinBandRejected=false;
+
+        for(std::size_t interfaceIndex=0;interfaceIndex+1<Layout.strates.size();++interfaceIndex)
+        {
+            const auto& upper=Layout.strates[interfaceIndex];
+            const auto& lower=Layout.strates[interfaceIndex+1];
+            std::int64_t minimumOffset=std::numeric_limits<std::int64_t>::max();
+            std::int64_t maximumOffset=std::numeric_limits<std::int64_t>::min();
+            std::int64_t maximumCrossingDepth=0;
+            std::int64_t minimumUpperThickness=std::numeric_limits<std::int64_t>::max();
+            std::int64_t minimumLowerThickness=std::numeric_limits<std::int64_t>::max();
+            std::uint64_t columns=0,skipped=0,holes=0,air=0,solid=0;
+            bool firstHoleReported=false;
+            const std::int64_t seam=upper.bedrock.bottomMicrometres;
+            const auto passageCoversColumn=[&](std::int64_t xUm,std::int64_t yUm,
+                std::int64_t zMinimumUm,std::int64_t zMaximumUm)
+            {
+                constexpr double Q=VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+                for(const auto& passage:Layout.passages)
+                {
+                    if(passage.upperStrateIndex!=upper.strateIndex
+                        ||passage.lowerStrateIndex!=lower.strateIndex)continue;
+                    for(std::size_t pointIndex=1;pointIndex<passage.controlPoints.size();++pointIndex)
+                    {
+                        const auto& a=passage.controlPoints[pointIndex-1];
+                        const auto& b=passage.controlPoints[pointIndex];
+                        const double ax=a.positionSubvoxels[0]*coreMicrometres/Q;
+                        const double ay=a.positionSubvoxels[1]*coreMicrometres/Q;
+                        const double az=a.positionSubvoxels[2]*coreMicrometres/Q;
+                        const double bx=b.positionSubvoxels[0]*coreMicrometres/Q;
+                        const double by=b.positionSubvoxels[1]*coreMicrometres/Q;
+                        const double bz=b.positionSubvoxels[2]*coreMicrometres/Q;
+                        const double radius=std::max(a.radiusSubvoxels,b.radiusSubvoxels)
+                            *coreMicrometres/Q+750000.0;
+                        if(std::max(az,bz)+radius<zMinimumUm
+                            ||std::min(az,bz)-radius>zMaximumUm)continue;
+                        const double dx=bx-ax,dy=by-ay;
+                        const double lengthSquared=dx*dx+dy*dy;
+                        const double t=lengthSquared>0.0
+                            ?std::clamp(((xUm-ax)*dx+(yUm-ay)*dy)/lengthSquared,0.0,1.0):0.0;
+                        const double ex=xUm-(ax+t*dx),ey=yUm-(ay+t*dy);
+                        if(ex*ex+ey*ey<=radius*radius)return true;
+                    }
+                }
+                return false;
+            };
+
+            for(std::int64_t iy=-XYExtentMicrometres/XYStepMicrometres;
+                iy<=XYExtentMicrometres/XYStepMicrometres;++iy)
+            for(std::int64_t ix=-XYExtentMicrometres/XYStepMicrometres;
+                ix<=XYExtentMicrometres/XYStepMicrometres;++ix)
+            {
+                const std::int64_t xUm=ix*XYStepMicrometres;
+                const std::int64_t yUm=iy*XYStepMicrometres;
+                const auto bands=VoxelForgeCore::EvaluateResolvedLayoutTransitionBandsV1(
+                    upper,lower,Owner.Seed,Layout.strateLayoutChunkSizeMicrometres,xUm,yUm);
+                const std::int64_t offset=bands.upperBedrockBottomMicrometres-seam;
+                minimumOffset=std::min(minimumOffset,offset);
+                maximumOffset=std::max(maximumOffset,offset);
+                maximumCrossingDepth=std::max(maximumCrossingDepth,
+                    bands.crossingDepthMicrometres);
+                minimumUpperThickness=std::min(minimumUpperThickness,
+                    bands.upperBedrockTopMicrometres-bands.upperBedrockBottomMicrometres);
+                minimumLowerThickness=std::min(minimumLowerThickness,
+                    bands.lowerCeilingTopMicrometres-bands.lowerCeilingBottomMicrometres);
+                const std::int64_t zMinimum=std::min(bands.upperBedrockBottomMicrometres,
+                    bands.lowerCeilingBottomMicrometres);
+                const std::int64_t zMaximum=std::max(bands.upperBedrockTopMicrometres,
+                    bands.lowerCeilingTopMicrometres);
+                if(passageCoversColumn(xUm,yUm,zMinimum,zMaximum)){++skipped;continue;}
+
+                ++columns;
+                bool hasHole=false;
+                for(std::int64_t zUm=zMinimum+zStepMicrometres/2;
+                    zUm<zMaximum-zStepMicrometres/2;zUm+=zStepMicrometres)
+                {
+                    const VoxelForgeCore::Vec3d point{
+                        static_cast<double>(xUm)/coreMicrometres,
+                        static_cast<double>(yUm)/coreMicrometres,
+                        static_cast<double>(zUm)/coreMicrometres};
+                    const float density=Field.densityAt(point);
+                    if(!std::isfinite(density)||density>=0.0f)
+                    {
+                        if(!firstHoleReported)
+                        {
+                            std::printf("[StrateTransitionFirstHole] x_um=%lld y_um=%lld z_um=%lld z_min_um=%lld z_max_um=%lld density=%.9g dispatch=%s\n",
+                                static_cast<long long>(xUm),static_cast<long long>(yUm),
+                                static_cast<long long>(zUm),static_cast<long long>(zMinimum),
+                                static_cast<long long>(zMaximum),density,
+                                Field.densityDispatchPathAt(point).c_str());
+                            firstHoleReported=true;
+                        }
+                        hasHole=true;++air;
+                    }
+                    else ++solid;
+                }
+                if(hasHole)++holes;
+            }
+
+            const std::int64_t boundaryPeakToPeak=maximumOffset-minimumOffset;
+            const std::int64_t allowedWidth=upper.transitionMode=="Hard"
+                ||upper.transitionFallsBackToHard?0:upper.transitionWidthMicrometres;
+            if(interfaceIndex==0)
+            {
+                auto wide=Layout;
+                wide.strates[0].transitionMode="Interleaved";
+                wide.strates[0].transitionFallsBackToHard=false;
+                wide.strates[0].transitionWidthMicrometres=8000000;
+                wide.strates[0].transitionInterpenetrationMicrometres=8000001;
+                std::vector<VoxelForgeCore::ResolvedLayoutIssueV2> issues;
+                std::string error;
+                negativeWidthRejected=!wide.validate(
+                    VoxelForgeCore::ResolvedLayoutValidationModeV3::strict,issues,error);
+
+                auto thin=Layout;
+                auto& bedrock=thin.strates[0].bedrock;
+                bedrock.topMicrometres=bedrock.bottomMicrometres+minimumBandMicrometres-1;
+                thin.strates[0].content.bottomMicrometres=bedrock.topMicrometres;
+                negativeThinBandRejected=!thin.validate(
+                    VoxelForgeCore::ResolvedLayoutValidationModeV3::strict,issues,error);
+            }
+            const bool passed=columns>0&&holes==0&&maximumCrossingDepth<=allowedWidth
+                &&minimumUpperThickness>=minimumBandMicrometres
+                &&minimumLowerThickness>=minimumBandMicrometres;
+            interfacesPassed+=passed?1u:0u;
+            totalColumns+=columns;passageColumnsSkipped+=skipped;
+            holeColumns+=holes;airSamples+=air;solidSamples+=solid;
+            std::printf("[StrateTransitionInterface] upper=%d lower=%d mode=%s width_um=%lld max_crossing_depth_um=%lld boundary_peak_to_peak_um=%lld allowed_um=%lld upper_min_band_um=%lld lower_min_band_um=%lld columns=%llu passage_columns=%llu hole_columns=%llu air_samples=%llu status=%s\n",
+                upper.strateIndex,lower.strateIndex,upper.transitionMode.c_str(),
+                static_cast<long long>(upper.transitionWidthMicrometres),
+                static_cast<long long>(maximumCrossingDepth),
+                static_cast<long long>(boundaryPeakToPeak),static_cast<long long>(allowedWidth),
+                static_cast<long long>(minimumUpperThickness),static_cast<long long>(minimumLowerThickness),
+                static_cast<unsigned long long>(columns),static_cast<unsigned long long>(skipped),
+                static_cast<unsigned long long>(holes),static_cast<unsigned long long>(air),
+                passed?"PASS":"FAIL");
+        }
+        const bool controlsPassed=negativeWidthRejected&&negativeThinBandRejected;
+        std::printf("[StrateTransitionNegativeControls] wider_than_declared=%s thinner_than_minimum=%s minimum_band_um=%lld status=%s\n",
+            negativeWidthRejected?"REJECTED":"ACCEPTED",
+            negativeThinBandRejected?"REJECTED":"ACCEPTED",
+            static_cast<long long>(minimumBandMicrometres),controlsPassed?"PASS":"FAIL");
+        const bool passed=!Layout.strates.empty()&&interfacesPassed+1==Layout.strates.size()
+            &&holeColumns==0&&airSamples==0&&controlsPassed;
+        std::printf("[StrateTransitionAuditSummary] interfaces=%llu passed=%llu columns=%llu skipped_passage_columns=%llu hole_columns=%llu air_samples=%llu solid_samples=%llu status=%s\n",
+            static_cast<unsigned long long>(Layout.strates.size()-1),
+            static_cast<unsigned long long>(interfacesPassed),
+            static_cast<unsigned long long>(totalColumns),
+            static_cast<unsigned long long>(passageColumnsSkipped),
+            static_cast<unsigned long long>(holeColumns),
+            static_cast<unsigned long long>(airSamples),
+            static_cast<unsigned long long>(solidSamples),passed?"PASS":"FAIL");
+        return passed;
+    }
+
     inline int RunPipelinedStreamingBenchmark(std::shared_ptr<FStandaloneOwnerWorld> OwnerWorld,
         const VoxelForgeCore::ResolvedWorldSnapshot& CoreSnapshot,
         const FVector& CameraPositionVoxels,int32 WorkerCount,int32 MaxLevel,
@@ -256,6 +422,7 @@ namespace StandaloneStreamBenchmark
         bool bAuditBasePageEquivalence=false,bool bAuditRouteParity=false,
         bool bAuditResolvedLayoutBoundaries=false,
         bool bAuditResolvedLayoutPassages=false,
+        bool bAuditStrateTransitions=false,
         const VoxelForgeCore::ResolvedLayoutSnapshotV3* ResolvedLayout=nullptr)
     {
         using Clock=std::chrono::steady_clock;
@@ -441,6 +608,14 @@ namespace StandaloneStreamBenchmark
             Streamer.Stop();
             std::fprintf(stderr,"[StreamPipeline] full shape build failed: %s\n",BuildError.c_str());return 2;
         }
+        if(bAuditStrateTransitions)
+        {
+            if(ResolvedLayout==nullptr||!CoreSnapshot.resolvedLayout())
+            {Streamer.Stop();std::fprintf(stderr,"[StrateTransitionAudit] missing resolved-layout snapshot\n");return 2;}
+            const bool passed=AuditResolvedStrateTransitions(Shape,World,*ResolvedLayout);
+            Streamer.Stop();
+            return passed?0:11;
+        }
         if(bAuditResolvedLayoutPassages)
         {
             if(ResolvedLayout==nullptr||!CoreSnapshot.resolvedLayout())