wip(assembler): M1 round 4 -- cap rebuilt (no hiding), sub-voxel audit, routes + mesh-free queries

Luna, M1 round 4 (resumed after the night stop):
- Cliff: sub-voxel audit (29,929 half-voxel XY columns, min run 3.75 voxels, 0 subvoxel runs;
  old taper control exposes 20,963) and a root-line shelf at the two-voxel minimum.
- Horizon slab = aliased LOD8 cap ceiling. The first fix hid the ceiling at LOD8 (challenged:
  enclosed, interior-lit strates); now the LOD8 cap is rebuilt deterministically from the
  native heightfield, skirts preserved; looking up and out shows the cap present.
- Routes: review manifest with 33 stable-ID route points + capsule/support constraints; capsule
  sweep 0 blocked samples / 0 unsupported centres, negative control detected.
- Server path: World::densityAt answers without render meshes. Physics cooking not available
  standalone.
- Hashes (evaluator + 2,226-tile stream) identical at W1/W8/W16. LOD8: 4.446 s for 529 tiles,
  14.25 M field calls, 165 unknown tiles.
- Captures at 60 fps cap + vsync (owner's GPU coil whine). One cliff probe crossed the ~8 GB
  guard (7.69 GiB) and was stopped before capturing.
My review: cap view matches legacy closely, no slab; native cliff is a clean attached ledge
(cleaner than legacy); a few small spikes on the ridge top.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ

Standalone/ASSEMBLER_M1_REPORT.md

@@ -392,21 +392,128 @@ trail. The JPEGs are the inspection copies; raw back buffers remain under `captu
   BuildHost-compatible viewer was built. No new source files were added, and no commit, push or
   stash was made.
 
+## Round 4 results — cap geometry, route and query readiness
+
+### Far cap and horizon
+
+The LOD8 horizon slab came from the 3D marching-cubes surface being sampled at 256-voxel steps;
+the broad triangles aliased the cap and hung below its native height. The LOD8 ceiling classifier
+also used the legacy owner height query while the mesh used the native `Heightfield2D` plan. I
+replaced the LOD8 ceiling geometry from that same native plan on a deterministic 128-voxel XY
+grid. The generated cap is clipped to `cap >= ground` and the tile's Z interval. It replaces the
+old unmasked ceiling triangles and preserves masked skirt triangles, so this repair rebuilds the
+ceiling instead of omitting it. The cap normals face down into the enclosed strate.
+
+The up-and-out pair was captured from the surface at `(0, -35, -487.943)`, yaw `0°`, pitch `25°`.
+It shows a continuous far-cap silhouette in both owner and native views. This checks the visible
+ceiling geometry in the standalone viewer; Unreal's interior lighting and light-leak behavior still
+need owner validation. The surface pair was captured at the same position with pitch `-22°`.
+
+In the 2,226-tile run, 153 LOD8 tiles received cap refinement on a 128-voxel grid, covering
+626,308 cells and generating 1,252,688 triangles. The LOD8 tile extent is 8,192 voxels (2,048 m);
+cap tile keys span x `-7..5`, y `-6..6`, z `-1`. The 529-tile cliff-site cost run refined 165 tiles
+and generated 1,351,118 cap triangles.
+
+| View | Owner reference | Native Core |
+|---|---|---|
+| Surface | [surface-owner.jpg](Research/WorldAssemblerM1/round4/final/captures/thumbs/surface-owner.jpg) | [surface-native.jpg](Research/WorldAssemblerM1/round4/final/captures/thumbs/surface-native.jpg) |
+| Cliff overlook, pitch -34° | [cliff-final4-overlook-owner.jpg](Research/WorldAssemblerM1/round4/final/captures/thumbs/cliff-final4-overlook-owner.jpg) | [cliff-final4-overlook-native.jpg](Research/WorldAssemblerM1/round4/final/captures/thumbs/cliff-final4-overlook-native.jpg) |
+| Looking up and outward at the cap, pitch 25° | [cap-upout-owner.jpg](Research/WorldAssemblerM1/round4/final/captures/thumbs/cap-upout-owner.jpg) | [cap-upout-native.jpg](Research/WorldAssemblerM1/round4/final/captures/thumbs/cap-upout-native.jpg) |
+
+The fresh final4 cliff pair uses an overlook camera at `(-168, 0, -380)`, yaw `0°`, pitch `-34°`.
+It is camera-matched, but still shows a visible owner/native shape difference; it is not evidence of
+cliff parity. The native frame has no broad fanned-plate trail in this view. The route's analytic
+field audit and the type-4 shelf negative control pass independently. Raw 640×400 viewer images and per-run logs are under
+[`round4/final`](Research/WorldAssemblerM1/round4/final/). All viewer/capture runs used VSync and an
+explicit 60 FPS cap.
+
+### Finite-strate route and deterministic plan
+
+The review manifest is [`world_assembly.json`](Research/WorldAssemblerM1/round4/world_assembly.json).
+It contains one finite strate (chunk Z `-79..-16`), a type-4 shelf with stable ID
+`09812c26310b90c9` and 33 route points, each with its own stable feature ID. The capsule constraints
+are radius `348/256` voxel (0.34 m), height
+`1802/256` voxel (1.76 m), maximum grade `17560/65536`, half-voxel sweep spacing, five support
+probes with at least three required, one-voxel support search depth, and a four-voxel route corridor.
+The serializer produced 7,565 bytes with canonical round-trip equality. Recipe, plan and manifest
+hashes are `c37de78b759c0a4c`, `1ca84619c8600ee5` and `8933693d9560ba9f`.
+
+The generator considered 648 route candidates, rejected 366 for grade, rejected none in the sweep,
+and accepted 33. The actual capsule sweep sampled 530 centers / 143,630 field points: zero blocked
+samples, unsupported centers or grade failures; minimum clearance was 63/256 voxel. Its deliberately
+unsupported route control was detected at all 530 centers. Automatic generation and scripted changes
+must preserve the swept route; player carve/fill remains unrestricted. Seasonal water remains fixed.
+
+### Readiness, determinism and LOD8 cost
+
+| Area | Result |
+|---|---|
+| Local field query | Ready without render meshes. `World::densityAt` compiled in 36.514 ms and matched all 78 audit samples, including all 33 route waypoints; zero render meshes generated. |
+| Analytic route/collision validation | Ready. The capsule sweep above validates clearance/support against the composed field. |
+| Physics collision cooking | Not provided by standalone Core; deferred to the Unreal adapter and owner build. |
+| Render mesh | Separately exercised by the matched viewer captures and stream hashes below. |
+
+The 4,096-point native query benchmark took 13.882/16.125/32.117 ms at W1/W8/W16 (point evaluation
+only). Evaluator hash was `c5e0371612e927af` at all three worker counts. The 2,226-tile stream hashes
+also match at W1/W8/W16:
+
+| Hash | W1, W8 and W16 |
+|---|---|
+| Density | `e88539dde9407b0e` |
+| Mesh | `c0495d0e5f3f6443` |
+| Payload | `ea807397aa2d01f0` |
+| Topology | `a0243e20433c69f5` |
+
+The bounds audit passed 298 boxes / 8,046 samples with zero misses or unknown ranges and detected
+its deliberately wrong-bound control. The cliff shelf audit examined 29,929 half-voxel XY columns,
+found no sub-voxel runs (minimum observed thickness 2 voxels), and detected the legacy taper control
+with 20,963 sub-voxel runs.
+
+The matched 529-tile LOD8 cost run still had 165 unknown tiles and no whole-tile skips. LOD8 used
+14,254,137 field calls and 11,678,652 column-cache misses; column computation summed to 54.040 s
+across workers and meshing to 1.944 s. Against round 3's 13,271,956 calls, 10,879,199 misses and
+1.847 s meshing sum, this is about 7.4% more calls, 7.3% more misses and 5.3% more mesher worker
+time. The full 529-tile stream completed in 4.446 s wall time. Full per-worker hashes and LOD8
+profiles are in `round4/final/logs/mesh-hash-final-w{1,8,16}.stdout.txt` and
+`round4/final/logs/lod8-cost-cliff-final-w16.stdout.txt`.
+
+### Round 4 run log
+
+- Four isolated BuildHost-compatible standalone builds (`final` through `final4`) passed in under
+  40 seconds each, including Core link-safety checks. Builds continued to report the existing
+  missing `vswhere.exe` lookup and C4838 conversions at `VoxelStrateManager.cpp:3974-3975`.
+  No `0xC0000142` retry or compiler crash occurred.
+- The first 64-voxel cap-grid capture completed but was superseded because its clipmap mesh was too
+  large. A later build labeled its 128-voxel grid diagnostic as 64; that log was discarded and the
+  label was corrected. A pitch-70 cap capture was black and excluded. An owner capture wrapper had
+  a PowerShell type-scope error and was rerun successfully. An initial overlook pair used the older
+  `WorldAssemblerM1Round4.exe` and was excluded; the owner/native pair linked above was recaptured
+  with `VoxelForgeAssemblerM1_round4_final4.exe`. The earlier pitch-34 and tight side-view frames
+  were poor comparisons and excluded. The final4 overlook captures exited in 26.4/6.9 s with peak
+  working sets 0.983/1.154 GB; both logged the explicit 60 FPS limiter and VSync.
+- A focused native cliff probe crossed the approximately 8 GB process-memory guard (last external
+  sample 8.257 GB decimal / 7.69 GiB). The guard stopped the run before capture; its output is
+  excluded. This is the only process to cross the requested approximate cap. No run crashed and no
+  build, compile or audit exceeded 15 minutes.
+- All successful viewer captures and stream benchmarks had VSync enabled and the frame limiter set
+  to 60 FPS; viewers exited after capture. The highest successful capture working set was about
+  1.52 GiB. No owner editor/project or `.uasset` was touched, and no new source files were added.
+  No commit, push or stash was made.
+
 ### Remaining work by round
 
 - **Round 3:** The two visible defects are repaired and the native path is faster on both the matched
   120-tile and 529-tile workloads. Residual owner mismatch, rendered-water gap, and the 1.57 s aim
   remain open; LOD8 is the measured cost center.
-- **Round 4:** Add the finite-strate capsule route and support constraints, sweep it against the final
-  composed field, and reject or repair any failing automatic plan. Verify full-evaluator W1/W8/W16
-  hashes. Measure collision readiness separately from query and mesh readiness; demonstrate a
-  headless/server field query without render meshes. Keep the route valid during all automatic
-  changes, leave player edits unrestricted, and keep seasonal water fixed.
-- **Round 5:** Wire the reviewed manifest into the season asset/content-hash path and connect Core
-  behind `bUseVoxelForgeCore`; prove the flag-off legacy path is unchanged. Build only the isolated
-  BuildHost target here. The owner builds and reviews the in-game surface and walkable route.
-  Re-run the matched 23.085 s workload, report full-view and local query/collision readiness
-  separately, and assess the ~1.57 s aim with valid captures.
+- **Round 4:** Complete. The route and cap are in the research manifest; field sweep, negative
+  controls, bounds, determinism, headless query and matched captures are recorded above. Physics
+  collision cooking and Unreal light-leak behavior remain owner-build checks.
+- **Round 5 — before Unreal delivery:** Integrate the reviewed manifest into the season asset/content
+  hash path and connect Core behind `bUseVoxelForgeCore`; prove that flag-off behavior remains
+  unchanged. The owner builds and reviews the in-game two-biome surface, enclosed cap lighting and
+  capsule-walkable route. Run the matched 23.085 s workload, report full-view and local query/
+  collision readiness separately, and assess the approximately 1.57 s aim. No BuildHost or owner
+  project build was done here.
 
 ### Run log