feat(editor): walk a composed candidate in PIE + why rooms read angular

PART B -- the thing Jahni asked for: "any way to test those in game?"
A candidate existed only as measurements and PNGs. Now he can stand in one.

  Select the VoxelWorld actor in PIE -> Live Edit|Composer ->
  ComposerSeed / ComposerCandidateIndex / ComposerTargetStrateIndex /
  bComposerRollStructure -> click Apply Composer Candidate.

The button and the automation tests call the SAME roll wrapper, which was
the load-bearing requirement: a second roll path could drift, and then he
would be judging a different world than the contact sheet describes. A
determinism sample is logged on apply (seed, index, recipe, archetype,
metrics, epoch, eight-point density verdict) so drift is caught the day it
happens rather than in a month.

Hazards handled, since this is the first composer code to touch the live
runtime path: preflight materialisation before any live mutation, generation
and decoration tasks drained, PassagesVersion bumped to invalidate
thread_local caches, reuse of the existing RegenerateAllChunks / Epoch
invalidation rather than a new path, no Initialize() or GeneratePassages()
during apply (the re-entrancy trap), DiffLayer locks untouched, and custom
recipes conservatively force ClassifyTile to Mixed.

Scope is deliberate: a DENSITY-ONLY overlay. Layout height, authored
passages, content, water and biome metadata stay from the existing slot;
RebuildStrates() clears it. A full composed layout replacement needs a safe
rebuild path that does not exist yet.

Editor-only, verified: a Shipping build succeeds with the bridge excluded
(96/96 actions), so §3.1's "offline only, never on a player's machine"
still holds.

⚠️ UNVERIFIED BY DESIGN: a button cannot be tested headlessly and Codex was
told not to claim it works. Jahni presses it and confirms the visual plus
the "determinism=PASS" log line.

PART A -- why rooms read angular, measured not guessed. One of three room
shapes is VoxelSDF::RoundedBox:
  ShapeA = (.8 Rxy, .8 Rxy, .8 Rz)   ShapeR = .25 Rxy
so rounding is 31% of the horizontal half-extent but 78% of the vertical.
Corners are rounded; the broad planar FACES survive. SmoothMin (blend 4)
softens room/tunnel junctions not isolated corners; the cave warp bends
geometry but preserves flat regions; roughness is surface-scale only.
The name is accurate -- "rounded box" is not "blob".

NOT ACTED ON. Jahni corrected his own read: the angular archetype is Maze
(lattice source, rectilinear BY DESIGN and correct), and TunnelNetwork is
"alright-ish". Codex's recommendation is recorded for if he ever wants it:
~5-10% boxes, 10-20% capsules, rest ellipsoids, or a larger ShapeR.

Also closed REVIEW_FINDINGS EVoxelPassageType/Style as WONTFIX, enacting a
2026-08-16 judgement that recommended closure and was left open.

Build clean (Editor + Shipping), 25 succeeded / 0 failed, run by me.

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

CODEMAP.md

@@ -413,13 +413,14 @@ Maps depth→strate at runtime; owns passages.
 | `AnyPassageNearBox` | — | Conservative sphere-vs-AABB test of every passage's bound against a voxel box (+carve blend pad). Per TILE (ClassifyTile guard), never per voxel. |
 | `FindSlotIndexForChunkZ` | 427 | Z → layout index. |
 | `GetStrateAt` / `GetStrateIndex` | 443 / 455 | World-Z queries. |
-| `GetLayoutVersion` | h:161 (inline) | Layout/passage generation counter (= `PassagesVersion`, bumped by every `Initialize`). Hot-path callers key `thread_local` memos on it (strate-index memo in `GetDensityWithParams`, passage shortlist) so editor rebuilds never serve stale data. |
+| `GetLayoutVersion` | h:161 (inline) | Layout/passage generation counter (= `PassagesVersion`, bumped by every `Initialize` and by the editor composer override). Hot-path callers key `thread_local` memos on it (strate-index memo in `GetDensityWithParams`, passage shortlist) so live changes never serve stale data. |
 | `GetStrateForChunk` | 466 | Chunk → definition. |
 | `GetGeneratorTypeForChunk` | 476 | Chunk → generator type. |
 | `UsesOperatorStackForChunk` | 559 | Chunk → should `GetDensityAt` take the operator stack? `bUseOperatorStack` on the definition **AND** archetype in the ported list — **now all 8 of 8** (Maze, FlatPlain, CrystalChamber, SurfaceWorld, VerticalShafts, FloatingIslands, TunnelNetwork, Underwater). **That list is written down here and nowhere else.** With every archetype ported the flag is now the *only* thing that decides the path, so ticking the box is no longer a no-op anywhere — it is a real switch onto the operator stack for that strate. |
 | `GetSlabParamsForChunk` | 490 | Slab params with runtime Z bounds (no blend — slabs use Hard). |
 | `GetBiomeContextForChunk` | — | Flatten the strate's `Biomes[]` + `BiomeMapParams` into a POD `FBiomeContext` for the biome field. Empty ⇒ biomes disabled. §8.14. |
 | `GetGenerationParams` | 515 | **Blended** TunnelNetwork params (handles Gradient/Hard/Interleaved transitions). |
+| `SetComposerOverrideForStrate` / `GetComposerOverrideForChunk` | editor-only | Temporary density-only candidate overlay for one existing slot. Copies immutable params/recipe into the worker refetch path, leaves layout/content/passages intact, and bumps `PassagesVersion` to invalidate generator memos. |
 | `BuildParamsFromDefinition` (static) | 1399 | Returns the definition's base `GenerationParams` only. Terrain-op assets are passed separately to `BuildChunkCache`, which applies one selected op per room and pre-bakes Column/Pit/Chimney features. |
 
 **`Public/VoxelTerrainOpDefinition.h` + `.cpp`** — `UVoxelTerrainOpDefinition : UPrimaryDataAsset`
@@ -462,7 +463,8 @@ selection → `FStrateGenerationParams::Lerp` or reflected native-family blend
 field range jitter (or the season-zero ±25% own-magnitude bootstrap for near-zero ranges) →
 editor-reflection clamps → ordered-pair repair. Bool
 `bTunnelsFlowTowardOrigin` inherits from the dominant parent; integer/enum SNAP fields are not
-jittered. This API is not called by runtime generation. The settings audit found **one unique path**,
+jittered. Normal runtime generation never calls this API; the editor-only AVoxelWorld bridge does so
+only from its PIE button. The settings audit found **one unique path**,
 `/Game/VoxelForge/DA_Strate3`, which explains the old one-vector corpus; the project assets were
 never in that pool.
 
@@ -475,6 +477,13 @@ it. `RequiredResources` / `ProvidedResources` close the room-state hole that cha
 could not express. `VoxelForgeComposerStructureRollTest` rolls 64 candidates, measures them through
 the offline sampler, and brute-forces every uniform box verdict from the novel stack itself.
 
+Public/VoxelWorld.h + Private/VoxelWorld.cpp — ApplyComposerCandidate exposes the four
+Live Edit|Composer properties and the CallInEditor button. It preflights the candidate, pauses
+generation before installing the manager override, and calls the existing epoch-aware full reset.
+The post-apply check compares eight densities against the shared native/recipe stack where the live
+world has no extra diff, disturbance, or biome context. It reports SKIPPED rather than comparing
+unlike fields.
+
 **`Public/VoxelStratePreview.h` + `Private/VoxelStratePreview.cpp`** — editor/automation-only PNG
 renderer and self-contained contact sheet. It consumes `FVoxelStrateSampleGrid` from the measurement
 pass, emits deterministic centre-Y XZ and data-selected XY slices via `IImageWrapper`, and shows filled-cell