wip(assembler): round L1 -- Linux baseline on abyss: Linux world identical to Windows

Headless Linux benchmark/hash tool (Clang 19 / GCC 14) sharing the viewer's plan builder and
streaming pipeline (moved verbatim into StreamBenchmarkPipeline.h / WorldAssemblyPrototype.h).
Owner Round17 view: density/mesh/payload/topology hashes equal the Windows S13 reference at
W1/W8/W12 (Clang, 3 runs each) and W8 (GCC), with -ffp-contract=off. No output change.
Baseline (i9-12900H, CPUs 0-11, powersave/balance_performance): whole view W8 3.562 s median,
W12 3.512 s, W1 16.555 s; peak RSS < 605 MiB.
Review: the default-stack crash is 17.3 MiB of static TLS per thread (glibc puts it in the
thread stack; HeightfieldColumnCache 6.8 MB), not recursion -- open, after S14.
MSVC compile of the viewer refactor not verified (no MSVC here).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Standalone/Compat/StandaloneDataAssetGlue.cpp

@@ -11,6 +11,11 @@ void UVoxelStrateDefinition::PostLoad()
     GenerationParams.bTunnelFloorEnabled = true;
 }
 
+FPrimaryAssetId UVoxelSeasonAsset::GetPrimaryAssetId() const
+{
+    return FPrimaryAssetId(TEXT("VoxelSeason"),GetFName());
+}
+
 bool UVoxelSeasonAsset::LoadManifest(FVoxelSeasonManifest& OutManifest, FString& OutReport) const
 {
     OutManifest = FVoxelSeasonManifest();