feat(runtime): the composed world can BE the game world

Jahni: "can you not implement those settings? as in, have them be live in
game?" This is that. The composer stops being a lab tool.

THE ARCHITECTURAL LINE, which is the whole design (COMPOSER-NOTES §3.1):
COMPOSITION stays editor-only, EVALUATION becomes runtime. Rolling,
measuring, preview, selection, promotion, the corpus -- none of it reaches
a player's machine. What crosses into the runtime is exactly two things:
reading a season manifest, and materialising a recipe into an op stack.

  UVoxelSeasonAsset      a cookable UPrimaryDataAsset holding the manifest,
                         so a season ships in a packaged game. The JSON
                         stays the reviewable, git-diffable artefact.
  UVoxelSettings::Season  optional. Unset => behaviour is exactly as today.
  GetEffective*()         season seed / spine radius / world radius / season
                         number override the authored values when assigned.
                         The test deliberately sets DIFFERENT authored
                         values, so "the season is authoritative" is proved
                         rather than coincidental.

⭐ MULTIPLAYER DETERMINISM, PROVED: two independent runtime managers built
the same season and compared 393,216 density samples BIT-IDENTICALLY. This
is the property the whole multiplayer model rests on -- replicate seed +
layout + diff, never geometry.

⭐ AND A STALE SEASON IS DETECTABLE, NOT SILENT. Initialize() now returns
bool and an assigned-but-invalid season NEVER falls back to the authored
pool. Falling back would hand a client a world that looks fine and is not
the season -- silent divergence, the worst failure mode in a shared world.
GetCurrentSeasonContentHash() is exposed BlueprintPure to compare at join.

HasComposerRecipeOverride() is gone. It force-classified every custom recipe
as Mixed, which was correct while box verdicts were only proved for
hand-written stacks -- but 8e346a3 made EffectOverBox correct in ISOLATION,
proved on a stack no builder produces. Keeping the force would have cost
tile skipping on every composed world forever.

VF_RollStrateRegionCount moved behind WITH_EDITOR while the partition-seed
helpers stayed runtime: rolling out, evaluation in. Lateral regions remain
gated off.

⚠️ Sol hit its usage limit mid-task, so the edits arrived unvalidated. I
built and ran them myself rather than assume -- and they did not compile:
VoxelForgeComposerSeasonTest.cpp was missing UObject/Package.h, which every
other test picks up transitively through the shared fixture it does not use.
One include; every NewObject/GetTransientPackage in the file was failing.

Editor build clean. SHIPPING BUILD SUCCEEDS -- the invariant that proves no
composer roller is linked into a packaged game. 30 succeeded / 0 failed.

⚠️ UNVERIFIED: whether it looks right on screen. Nothing headless can tell
us that; it needs Jahni to assign a season asset and press play.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VJiTcTSDNkKBtnNdiBtdaU

Source/VoxelForge/Private/VoxelStrateComposer.cpp

@@ -28,6 +28,7 @@
 #include <type_traits>
 #include <utility>
 
+#if WITH_EDITOR
 namespace
 {
     constexpr float GJitterFraction = 0.15f;
@@ -2262,27 +2263,6 @@ namespace
     }
 }
 
-bool FVoxelStrateMeasuredMetrics::IsUsable() const
-{
-    return bValid
-        && NumSampled > 0
-        && NumAir > 0
-        && NumSolid > 0
-        && NumSampled == NumAir + NumSolid
-        && NumAirComponents > 0
-        && LargestComponentCells > 0
-        && AirComponentCells.Num() == NumAirComponents
-        && FMath::IsFinite(AirFraction)
-        && FMath::IsFinite(LargestComponentShare)
-        && FMath::IsFinite(WalkableFraction)
-        && FMath::IsFinite(WalkableFloorAreaFraction)
-        && FMath::IsFinite(LargestWalkableSurfaceShare)
-        && FMath::IsFinite(MedianFeatureScale)
-        && FMath::IsFinite(LargestComponentPoint.X)
-        && FMath::IsFinite(LargestComponentPoint.Y)
-        && FMath::IsFinite(LargestComponentPoint.Z);
-}
-
 FVoxelStrateMeasuredMetrics VF_SummarizeStrateMetrics(
     const FVoxelStrateMetrics& Metrics)
 {
@@ -3901,22 +3881,6 @@ uint32 FVoxelStrateCorpus::GetContentsHash() const
     return Hash;
 }
 
-const TCHAR* VF_GetStrateArchetypeName(ECaveGeneratorType Archetype)
-{
-    switch (Archetype)
-    {
-    case ECaveGeneratorType::TunnelNetwork:  return TEXT("TunnelNetwork");
-    case ECaveGeneratorType::FlatPlain:      return TEXT("FlatPlain");
-    case ECaveGeneratorType::CrystalChamber: return TEXT("CrystalChamber");
-    case ECaveGeneratorType::Maze:            return TEXT("Maze");
-    case ECaveGeneratorType::SurfaceWorld:    return TEXT("SurfaceWorld");
-    case ECaveGeneratorType::VerticalShafts:  return TEXT("VerticalShafts");
-    case ECaveGeneratorType::FloatingIslands: return TEXT("FloatingIslands");
-    case ECaveGeneratorType::Underwater:      return TEXT("Underwater");
-    }
-    return TEXT("Unknown");
-}
-
 const TCHAR* VF_GetStrateCorpusProvenanceName(EVoxelStrateCorpusProvenance Provenance)
 {
     switch (Provenance)
@@ -4400,6 +4364,7 @@ bool FVoxelStrateCorpus::SetMeasuredMetrics(
     }
     return false;
 }
+#endif // WITH_EDITOR — corpus loading, promotion and parameter/structure roll implementation
 
 void VF_SetStrateArchetypeRuntimeBounds(
     FVoxelStrateArchetypeParams& Params, float TopWorldZ, float BottomWorldZ)
@@ -4589,11 +4554,13 @@ namespace VoxelStrateRegionPrivate
     }
 }
 
+#if WITH_EDITOR
 int32 VF_RollStrateRegionCount(int32 Seed, int32 StrateIndex)
 {
     return 1 + static_cast<int32>(VoxelHash::Cell(
         StrateIndex, StrateIndex ^ 0x6D, static_cast<uint32>(Seed) ^ 0x524F4C4Cu) % 3u);
 }
+#endif
 
 uint32 VF_GetStrateRegionPartitionSeed(int32 Seed, int32 StrateIndex)
 {
@@ -4753,6 +4720,7 @@ FVoxelStrateRegionBoxProof VF_AnalyzeStrateRegionBox(
     return Proof;
 }
 
+#if WITH_EDITOR
 FVoxelStrateRollInfo VF_RollStrateParamsDetailed(const FVoxelStrateCorpus& Corpus,
                                                  int32 Seed, int32 Index)
 {
@@ -5694,3 +5662,4 @@ bool VF_AreStrateStructureRecipesIdentical(const FVoxelOpStackRecipe& A,
     }
     return true;
 }
+#endif // WITH_EDITOR — no roller/corpus entry point is compiled into Shipping