research(step2d): a simpler field is fast (81 ns/sample) -- but it is not the owner's world; NOT a pass

Editor-only, default off (voxel.ResearchRedefinedDensityField). The redefined field is a seeded,
periodic cross-corridor pattern per strate plus the authored passages, landings and a shaft tree,
with four value-noise detail bands at every near-surface 25 cm sample and sound 8^3 brick proofs.
259^3 ring, six workers: 308 ms median (467 ms without skips) vs 8.9 s for the live field.
Detail, boundary-artefact, determinism (1 vs 6 workers, two runs) and bound-audit checks pass.

Why it is not a pass: the slices show a mostly-solid field with a few straight corridors, where the
owner's world is mostly open space; rooms, the tunnel network, composer recipes and archetypes are
gone. Much of the speed comes from 60% of bricks being proven solid in that simpler world.
What it does show: detail at full resolution plus brick skipping costs ~80-130 ns/sample; the
cost of the live field is how rooms/tunnels/passages are represented, not the detail or the lattice.

The two walkability tests were redirected to the research field in the working tree; that change
is NOT committed (saved as scratchpad step2d-test-redirect.patch) so they keep testing the live world.

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

Source/VoxelForgeEditor/Private/VoxelForgeRegionEvalExperiment.h

@@ -26,6 +26,9 @@ namespace VoxelForgeRegionEval
         double GeneralPathEntriesPerSample = 0.0;
         double WallSeconds = 0.0;
         double WorkerCpuSeconds = 0.0;
+        double BrickClassificationSeconds = 0.0;
+        double DensityEvaluationSeconds = 0.0;
+        double UniformFillSeconds = 0.0;
         double NanosecondsPerSample = 0.0;
         bool bWorkerCpuFromOsThreadTimes = false;
         bool bRegionProgram = false;
@@ -34,6 +37,16 @@ namespace VoxelForgeRegionEval
         uint64 RawFloatHash = 0;
         uint64 SaturatedSamples = 0;
         uint64 NonFiniteSamples = 0;
+        uint64 BrickCount = 0;
+        uint64 SkippedBricks = 0;
+        uint64 SkippedSamples = 0;
+        uint64 MacroBrickChecks = 0;
+        uint64 MacroCentreEvaluations = 0;
+        uint64 UnsupportedBrickProofs = 0;
+        uint64 ChunkBoundaryBrickProofs = 0;
+        uint64 PassageBoundBrickProofs = 0;
+        uint64 MixedMacroBrickProofs = 0;
+        double LongestWorkerWallSeconds = 0.0;
         uint64 SdfCacheBuilds = 0;
         uint64 ActiveOpListBuilds = 0;
         uint64 BroadPhaseIndexBuilds = 0;
@@ -122,6 +135,17 @@ namespace VoxelForgeRegionEval
         int32 RequestedWorkerCount = WorkerCount,
         bool bCollectWholeRunCounters = false);
 
+    /** Full-resolution step 2d field pass with sound world-aligned 8^3 brick proofs. */
+    bool EvaluateRedefined(
+        const UVoxelGenerator& Generator,
+        FIntVector OriginVoxels,
+        int32 Dimension,
+        int32 RequestedWorkerCount,
+        float DetailScale,
+        TArray<float>& OutDensities,
+        FTiming& OutTiming,
+        bool bEnableBrickSkips = true);
+
     /** Count exact room/tunnel/core/passage candidate visits with instrumentation enabled. */
     FCandidateVisits CountCandidates(
         const UVoxelGenerator& Generator,