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

ARCHITECTURE.md

@@ -1186,6 +1186,15 @@ The route law applies to generation and automatic changes; player carve/fill edi
 This is standalone Core evidence; it is not yet connected to the season asset/hash path or reviewed in
 the owner's game.
 
+The round-4 horizon audit traced the false low slab to the LOD8 three-dimensional marching-cubes cap
+surface sampled on a 256-voxel lattice; the Core mesh's cap classification also consulted the legacy
+owner height oracle. LOD8 now samples the planned cap directly as a 2D heightfield on a 128-voxel grid,
+clips cells at the ground and tile-Z limits, and keeps existing ceiling seam skirts. This preserves a
+closed cap surface rather than deleting its index run. The viewer defaults to a 60 FPS ceiling and
+accepts `--frame-limit=1..60`, including while its window is occluded. See
+[`Standalone/ASSEMBLER_M1_REPORT.md`](Standalone/ASSEMBLER_M1_REPORT.md) for the matched up-and-out
+captures, cap tile counts, determinism hashes, route sweep and query/collision readiness split.
+
 ## 9. Multiplayer model (listen-server first, dedicated-friendly)
 
 > **Status: transport is DESIGN ONLY — nothing is networked in-tree yet** (no `Replicated`/`HasAuthority`/RPCs; a