passages: tunnels own their floor - flat-bottomed tube + solid shell (L109, v217) - pending visual review

Owner design: flat world-horizontal floor (0.50 m corner blend), 0.75 m solid shell written only
where the host field is air (interiors union first and beat every shell), 5 m cubic mouth ramps.
Removed route support restoration, deferred support, support columns, mouth-support restoration
and their capsule checks (-5,129 / +1,641 lines). Near-ready @W12: FI 1.39 -> 0.86, TN 1.29 ->
0.90, VS 0.85 -> 0.74, SW 0.70 -> 0.76 s (more shell/skirt surface). All walk audits pass;
Clang/GCC W1/W8/W12 deterministic; fast tier PASS; Linux UE builds; 6 UE arrival traces pass.
OPEN ISSUE: open-air shell (e.g. passage 0-1, 1037-1489 m route span) shows a regular stepped
banding pattern - not merged into assembler/world until fixed/approved.

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

Standalone/Source/OwnerWorldLoader.h

@@ -24,37 +24,6 @@ struct FStandaloneParitySample
     int32 StrateIndex = INDEX_NONE;
 };
 
-struct FStandalonePassageVoidCrossing
-{
-    std::size_t passageIndex=0;
-    std::size_t firstSegment=0;
-    std::size_t lastSegment=0;
-    std::uint64_t unsupportedSamples=0;
-    double unsupportedLengthMetres=0.0;
-    std::array<double,4> startPoint{};
-    std::array<double,4> endPoint{};
-    bool needsColumn=false;
-    bool connectedAtStart=false;
-    bool connectedAtEnd=false;
-    std::int64_t centerXSubvoxels=0;
-    std::int64_t centerYSubvoxels=0;
-    std::int64_t topZSubvoxels=0;
-    std::int64_t bottomZSubvoxels=0;
-    std::int64_t minimumRadiusSubvoxels=0;
-    std::int64_t nominalRadiusSubvoxels=0;
-    std::int64_t maximumRadiusSubvoxels=0;
-    double naturalSurfaceReliefMetres=0.0;
-    double maximumRouteOffsetMetres=0.0;
-    double maximumBoreRadiusMetres=0.0;
-    bool needsRootTaper=false;
-};
-
-struct FStandalonePassageVoidCrossingCache
-{
-    std::mutex mutex;
-    std::unordered_map<std::string,std::vector<FStandalonePassageVoidCrossing>> byLayout;
-};
-
 struct FStandaloneOwnerWorld
 {
     std::unique_ptr<UVoxelSettings> Settings;
@@ -81,8 +50,6 @@ struct FStandaloneOwnerWorld
     std::uint32_t StrateLayoutChunkSizeMicrometres = 8000000;
     std::int64_t StrateLayoutChunkWidthSubvoxels = 8192;
     bool bHasUnrealResolvedCorePlan = false;
-    std::shared_ptr<FStandalonePassageVoidCrossingCache> PassageVoidCrossingCache =
-        std::make_shared<FStandalonePassageVoidCrossingCache>();
 };
 
 namespace StandaloneOwnerLoader