fix: signed-overflow UB in VoxelHash made cave placement compiler-dependent; all generators LOD0-8; speed matrix (L60)

VoxelHash::Cell/Pair, legacy Cellular3D and the shared Core cellular hash added 0x7FFFFFFF to a signed
int32 before casting to uint32; overflow is undefined, so Clang and GCC placed cave passage 1 differently
(first differing sample at LOD1 tile (0,64,-512)). The bias is now done in unsigned arithmetic, in both the
standalone copy and the Unreal plugin header (Source/VoxelForge/Public/VoxelCaveMorphology.h). Native
caves, motifs and lattice now stream LOD0-8 with skirts and cross-level transitions. New verify.py
--speed-matrix runs every generator on one asserted-identical view (5 interleaved runs): motifs 1.33,
profiles 1.30-1.32, caves 1.41, natural SW 1.67, lattice 1.70, FI 4.93 s whole view. fast/medium/full PASS,
Clang/GCC peer hashes equal. Research R29 (open-edge ledge) and R30 (compiler-divergence suspects).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

Standalone/Source/StreamBenchmarkHeadless.cpp

@@ -1648,13 +1648,17 @@ int main(int argc,char** argv)
     if(!ParseOptions(argc,argv,options))return 2;
     if(options.TlsProbeRequested)
         return StandaloneTlsProbe::Run(options.TlsProbeWorkers,options.TlsProbeTouch);
-    std::printf("[HeadlessConfig] data=%s workers=%d clip_radius=%d max_clip_level=%d max_level=%d hash=%s column_overlap=%s force_generate=%s recipe=%s shared_column_cache=%s camera_step_m=(%.3f,%.3f,%.3f) seed_override=%s render_distance_override=%s\n",
+    std::printf("[HeadlessConfig] data=%s workers=%d clip_radius=%d max_clip_level=%d max_level=%d hash=%s column_overlap=%s force_generate=%s recipe=%s lattice_strate=%d shared_column_cache=%s camera_step_m=(%.3f,%.3f,%.3f) camera_override=%s camera_m=(%.6f,%.6f,%.6f) camera_rotation_deg=(%.3f,%.3f) seed_override=%s render_distance_override=%s\n",
         options.DataPath.string().c_str(),options.WorkerCount,options.ClipRadius,options.MaxClipLevel,
         options.MaxLevel,options.StreamHash?"on":"off",options.ProfileColumnOverlap?"on":"off",
         options.ForceGenerate?"on":"off",options.CavesRecipe?"caves"
+            :options.LatticeRecipe?"lattice"
             :options.FloatingIslandsRecipe?"floating-islands":"surface-world",
+        options.LatticeStrateIndex,
         options.UseSharedColumnCache?"on":"off",options.CameraStepMeters.X,options.CameraStepMeters.Y,
-        options.CameraStepMeters.Z,
+        options.CameraStepMeters.Z,options.HasCamera?"yes":"no",options.CameraMeters.X,
+        options.CameraMeters.Y,options.CameraMeters.Z,options.CameraYawDegrees,
+        options.CameraPitchDegrees,
         options.HasSeedOverride?"yes":"no",options.HasRenderDistanceOverride?"yes":"no");
     std::printf("[ColdTimeline] stage=owner_data_load begin_ms=%.3f\n",
         std::chrono::duration<double,std::milli>(Clock::now()-coldStart).count());