core: Vertical Shafts on the shared Core cave planner (L139, v237; 15/16 seeds)

Shaft mode reuses PlanResolvedCavernNetworkV1 with a capped full-height cylinder primitive (shapeKind=1), ledges,
access bores and cross links; 11 VerticalShaftParams fields mapped. Basal law: arrival 2-3 to a walkable terminal
landing; drops/climbs stay reporting tiers. Seed 2 fails shell/seams at the 2-3 arrival mouth (3 variants tried,
stopped per AGENTS.md). Whole view faster than assembler/world in 8/8 cells; near-ready slower in 7/8.
Source/: VoxelForgeCoreAdapter.cpp.

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

CODEMAP.md

@@ -174,7 +174,7 @@ remains `0`, and lateral regions remain gated off.
 | `../../VoxelForgeCore/Private/ModuleEntry/` | Unreal module entry and an isolated `CoreMinimal.h` shim for the actual engine header. |
 | `../../Standalone/Core/include/VoxelForgeCore/VoxelForgeCore.h` | Standard-library-only public Core API. `VOXELFORGECORE_API` exports the API from the Unreal module and is empty for standalone builds. |
 | `../../Standalone/Core/include/VoxelForgeCore/VoxelForgeCore.h` / `../../Standalone/Core/src/ResolvedLayoutInternal.h` | `ResolvedLayoutSnapshotV3`: physical layout-chunk width, versioned micrometre intervals, owned ceiling/content/bedrock bands, honored transition settings, deterministic per-column transition bands, recipe anchors, director-planned passages, canonical JSON/FNV identity, compatibility/strict validators, and negative-control audit. Built once from the director-resolved plan and consumed by bounds planning, Core dispatch, composition, and validation. §8.40–8.42, §8.46. |
-| `ResolvedLayoutStratePassageCapabilitiesV1::{hasNativeCaveField,hasNativeLatticeField}`, `IsNativeLatticeFieldStratum`, `HasNativeGraphField` | `Standalone/Core/include/VoxelForgeCore/VoxelForgeCore.h` / `Standalone/Core/src/ResolvedLayoutInternal.h` | Explicit per-strate native graph capability; `Core.Lattice.PrimitiveField` is restricted to Maze/VerticalShafts recipe version 1. Lattice seeds include world seed, strate, recipe version and stable feature ID; explicit polyline records keep their endpoints and receive conservative bounds. §8.54. |
+| `ResolvedLayoutStratePassageCapabilitiesV1::{hasNativeCaveField,hasNativeLatticeField}`, `IsNativeLatticeFieldStratum`, `HasNativeGraphField` | `Standalone/Core/include/VoxelForgeCore/VoxelForgeCore.h` / `Standalone/Core/src/ResolvedLayoutInternal.h` | Explicit per-strate native graph capability; `Core.Lattice.PrimitiveField` remains Maze/VerticalShafts recipe version 1, and `Core.Caves.PrimitiveField` also accepts VerticalShafts in L139. Lattice seeds include world seed, strate, recipe version and stable feature ID; explicit polyline records keep their endpoints and receive conservative bounds. §8.54, §8.56. |
 | `FCavernRuntimeFeature::FSegmentNode`, `ApplyResolvedNativeCavesField`, `ClassifyNativeCaveFieldBox` | `Standalone/Core/src/ShapeWorldInternal.h` | A deterministic nested segment BVH accelerates native graph distance and conservative interval evaluation; the outer graph BVH still supplies tile candidates and protects `isTileShapeFree`. The 0.4 m feature-union width is separate from the floor fillet width. §8.54. |
 | `../../Standalone/Core/src/FloatingIslandsInternal.h` | Canonical standalone/Core floating-island planner, geometry-versioned field, manifest serializer, influence bounds, capsule-route checks, and thickness audit. |
 | `ApplyOwnerFourStratePlan` | `Source/VoxelForgeEditor/Private/VoxelForgeExploreCommandlet.cpp` | BuildHost-only transient fixed-slot plan from the four staged owner strate assets; leaves the authored settings and strate packages untouched. |
@@ -1352,6 +1352,20 @@ tunnel-slope version in `VoxelStrateDefinition.cpp`, plus the standalone `VoxelF
 in `VoxelForgeExploreCommandlet.cpp`. `GetStrateForChunk` still receives layout-chunk Z, not a Core
 tile index. See `Standalone/Research/WorldAssemblerM3/Unreal1/REPORT.md` for BuildHost evidence.
 
+### 3.38 Native Vertical Shafts graph field — World Assembler M3 L139
+
+| Symbol | Canonical file | Role |
+|---|---|---|
+| `ResolvedCavernPlannerSettingsV1::verticalShaftMode`, basal terminal route planning | `Standalone/Core/include/VoxelForgeCore/VoxelForgeCore.h`, `Standalone/Core/src/ResolvedLayoutInternal.h` | Extends shared `PlanResolvedCavernNetworkV1` for an arrival-only basal strate; its walk-only spine terminates at a landing above bedrock. Shaft mode disables generic branches and uses dedicated shaft nodes. |
+| `ResolvedCavernRoomV1::shapeKind=1`, `ApplyResolvedNativeCavesField` | `Standalone/Core/src/ShapeWorldInternal.h` | Evaluates capped vertical shaft cylinders with shelves alongside shared access and cross-connect tunnels. Uses `Core.Caves.PrimitiveField`, not the L58 lattice spiral. |
+| VerticalShafts settings mapping | `Standalone/Source/WorldAssemblyPrototype.h` | Maps the 11 legacy params into shared spacing, room density/radii, bore radius, cross-connect density, ledges, roughness, and existing boundary seal/density bands. |
+| `IsNativeCaveFieldStratum`, S3 binding and `FCavesFieldAdapter` | `Standalone/Core/src/ShapeWorldInternal.h`, `Source/VoxelForge/Private/VoxelForgeCoreAdapter.cpp` | Reports `VerticalShafts` as `Core.Caves.PrimitiveField` v1 / `Caves-native`; leaves the legacy generator archetype identity intact. |
+| `RunL139SeedSweep.py`, `RunL139Determinism.py`, `RunL139Captures.py`, `RunL139WholeLayerCapture.py`, `RunL139FinalTiming.py` | `Standalone/Research/WorldAssemblerM3/Linux139/` | Reproducible composed 16-seed audit, Clang/GCC W1/W8/W12 identity check, five before/after eye-height views plus density-cutaway and plan-projection outside views, and L80 characterization. The seed-2 passage-shell failure blocks promotion. |
+
+See ARCHITECTURE §8.56 and
+[`Standalone/Research/WorldAssemblerM3/Linux139/REPORT.md`](Standalone/Research/WorldAssemblerM3/Linux139/REPORT.md)
+for the planner semantics, field mapping, audit result, captures, and outstanding shell failure.
+
 ## 4. The density pipeline (most-edited hot path)
 
 ### 4.1 `GetDensityWithParams` (TunnelNetwork) — VoxelGenerator.cpp:3749