wip(L27, side branch): passages cross open voids inside shared natural rock columns

Unsupported passage runs > 12.5 m become a solid relief-bearing column (ceiling/island to
ground, flared base) with the helix inside, for every recipe; FI anchor uses the same path.
All 4 styles x both recipes: 0/0/0, 0 open-air, naturalness pass; no-long-bridge audit (L26
fails it). Deterministic, Clang = GCC. Look approved; cost +35% SW / +19% FI blocks merge (L28).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CSFYgsdW8ejZSyiMf4qRSX

Standalone/Source/OwnerWorldLoader.h

@@ -24,7 +24,7 @@ struct FStandaloneParitySample
     int32 StrateIndex = INDEX_NONE;
 };
 
-struct FStandalonePassageBridgeRange
+struct FStandalonePassageVoidCrossing
 {
     std::size_t passageIndex=0;
     std::size_t firstSegment=0;
@@ -33,12 +33,24 @@ struct FStandalonePassageBridgeRange
     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 maximumRouteOffsetMetres=0.0;
+    double maximumBoreRadiusMetres=0.0;
 };
 
-struct FStandalonePassageBridgeCache
+struct FStandalonePassageVoidCrossingCache
 {
     std::mutex mutex;
-    std::unordered_map<std::string,std::vector<FStandalonePassageBridgeRange>> byLayout;
+    std::unordered_map<std::string,std::vector<FStandalonePassageVoidCrossing>> byLayout;
 };
 
 struct FStandaloneOwnerWorld
@@ -66,8 +78,8 @@ struct FStandaloneOwnerWorld
     std::uint32_t CoreVoxelSizeMicrons = 250000;
     std::uint32_t StrateLayoutChunkSizeMicrometres = 8000000;
     std::int64_t StrateLayoutChunkWidthSubvoxels = 8192;
-    std::shared_ptr<FStandalonePassageBridgeCache> PassageBridgeCache =
-        std::make_shared<FStandalonePassageBridgeCache>();
+    std::shared_ptr<FStandalonePassageVoidCrossingCache> PassageVoidCrossingCache =
+        std::make_shared<FStandalonePassageVoidCrossingCache>();
 };
 
 namespace StandaloneOwnerLoader