wip(step3): 12.5 cm voxels, fall-through fixed, brick evaluator in game, organic tunnels -- speed gate FAILS

Stopped by the owner's decision (in-game lit captures were eating the round); he judges the look in
game instead.
1. Fall-through with the research field: fixed. Deep drop, gate on: 2 holds (0.50 s), min foot
   clearance +43 cm; gate off: penetrates (-278 cm). Stress fixture offsets converted to metres.
2. VOXEL_SIZE 25 -> 12.5 cm. Physical sizes kept in metres (player, steps, gate, insets, research
   field sizes, dig radii, test thresholds); class defaults that count chunks/voxels doubled
   (ClipRadius 6, RenderDistanceChunks 1536, ViewDistance*, StrateViewMargin 6,
   PawnCollisionRadius 2, SkirtCells 4, EdgeSealThickness 128, decoration spacings, density volume
   res 256). Asset values override these defaults: the owner must double his own.
   Ring scale, six workers, idle, step-2f field before the look changes: 64 m cube (519^3) 4.55 s;
   32 m cube (259^3) 0.95 s.
3. In game: tiles go through the brick evaluator (proved by a log marker); profile switch rebuilds
   the loaded world (~5,800 tiles); full-detail fill 12.4 s after spawn in the visible-window test.
4. Look: round winding tunnels, per-column ellipsoid/lattice caches. All step-2f geometry gates pass
   at 12.5 cm (0 crumbs, 1 solid component per profile, solid share 69-87%). 259^3 ring, six workers:
   1.08-2.02 s (worst HyperComplex) -- the 600 ms gate FAILS. Lit captures failed (hidden/off-screen
   window, then blank frames); not pursued.

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

Source/VoxelForge/Private/VoxelContentManager.cpp

@@ -723,7 +723,7 @@ void UVoxelContentManager::BuildCellSpawns(const UVoxelGenerator* Gen, const FTr
     {
         // INTEGER voxel jitter: columns land on integer XY so the generator's surface-column cache
         // (T1.a, §8.10) applies — FRACTIONAL XY recomputes the noise-heavy heightfield+biome on EVERY
-        // sample. A 25 cm grid offset is imperceptible; random yaw/scale still breaks up the regularity.
+        // sample. A 12.5 cm grid offset is imperceptible; random yaw/scale still breaks up the regularity.
         const uint32 HJ = DecoHash(Cell.X, Cell.Y, gx, gy, -1, 0, InSeed, 0x10C0u);
         const int32 JX = FMath::Min(Spacing - 1, (int32)(VoxelHash::ToFloat01(HJ) * (float)Spacing));
         const int32 JY = FMath::Min(Spacing - 1, (int32)(VoxelHash::ToFloat01(VoxelHash::Mix(HJ ^ 0x68BC21EBu)) * (float)Spacing));