standalone: speed round 2 -- far biome colour grid (payload -365 ms), whole view 1.90 s @8w full payload

- Per-vertex biome lookup was the payload cost (~365 ms); far tiles now take the biome palette from a
  per-tile grid. Same channels (palette, slope, border blend, UV) and ceiling/ground sections.
- Opt-in --max-clip-level=8: 6,498 -> 2,226 tiles, stream 0.876 -> 0.428 s, 1.451 s process wall.
  Kept opt-in: six fixed views cannot prove every distant thin stratum survives.
- W1/W8 hashes equal across 11 outputs; routes 5642/5642; five captures pixel-identical, passage
  382 px differ (max delta 16).
- Rejected with measurements: LOD6 empty-block proof (-21% samples, no wall gain), far supertiles
  (no complete groups exist).
Remaining long pole: shape compile 0.854 s.

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

Standalone/Source/StreamingWorld.h

@@ -397,10 +397,13 @@ public:
                                            const FStandaloneMeshCache* InMeshCache=nullptr,
                                            int32 InMaxLevelFilter=-1,
                                            bool bInSkipUvAndColors=false,
-                                           bool bInSkipMaterialGroups=false)
+                                           bool bInSkipMaterialGroups=false,
+                                           bool bInSkipUV=false,
+                                           bool bInSkipColors=false)
         :World(&InWorld),WorkerCount(FMath::Clamp(InWorkerCount,1,16)),bHashDensity(bInHashDensity),
          MeshCache(InMeshCache),MaxLevelFilter(InMaxLevelFilter),
-         bSkipUvAndColors(bInSkipUvAndColors),bSkipMaterialGroups(bInSkipMaterialGroups)
+         bSkipUvAndColors(bInSkipUvAndColors),bSkipMaterialGroups(bInSkipMaterialGroups),
+         bSkipUV(bInSkipUV),bSkipColors(bInSkipColors)
     {
         VoxelGenLOD::InitializeConsoleSwitches();
         UVoxelMarchingCubesMesher::InitializeConsoleSwitches();
@@ -543,6 +546,8 @@ private:
         UVoxelMarchingCubesMesher Mesher;
         Mesher.SetGenerator(World->Generator.get());
         Mesher.bStandaloneSkipUvAndColors=bSkipUvAndColors;
+        Mesher.bStandaloneSkipUV=bSkipUV;
+        Mesher.bStandaloneSkipColors=bSkipColors;
         Mesher.bStandaloneSkipMaterialGroups=bSkipMaterialGroups;
         Mesher.bGenerateSkirts=World->bGenerateSkirts;
         Mesher.SkirtCells=static_cast<float>(World->SkirtCells);
@@ -635,6 +640,8 @@ private:
     int32 MaxLevelFilter=-1;
     bool bSkipUvAndColors=false;
     bool bSkipMaterialGroups=false;
+    bool bSkipUV=false;
+    bool bSkipColors=false;
     std::atomic<uint64> CacheHitCount{0};
     mutable std::mutex Mutex;
     std::condition_variable Wake;