perf(generation): exact worm block skip with a proven 3D Perlin bound -- measured NEUTRAL

The sampler put the worm carve's first noise call (VoxelGenerator.cpp:3985, FusedWorm) at 19.4% of
LOD0. The worm only carves where N1 + N2 < T with N2 >= 0, so where N1 >= T it contributes nothing,
bit for bit. A block proven to have N1 >= T everywhere can skip both noise calls exactly.

- The Lipschitz bound for this Perlin3D implementation: L = (15/4) * sqrt(3) * 1.25 = 8.118988160,
  in scaled-N1 units, with a 1e-3 float-rounding margin. Adversarial sampling found a worst ratio
  of 3.187 (0.39 L). The existing 2D floor-relief bound (8.5) is a component bound of a different
  field and was confirmed not to transfer.
- A soundness test that can fail (VoxelForgeWormBlockSkipTest): 6,476 proved blocks, 355,945 exact
  lattice samples, 0 violations. A deliberately halved L proves a bad block; the full L rejects it.
- voxel.WormBlockSkip, default 1.

Field exact: export OBJ byte-identical (b3e5f4c3..9b377), 841/841 keyed tiles identical to
NextHeadStaticTrace_20260913, capability 20,830 / 10,909.

RESULT, stated plainly: no measurable speed gain. The skip rate is 4.07% of worm-eligible LOD0
samples and 0% at LOD1-4, because the bound is ~2.5x looser than the worst observed ratio at the
block size used. Paired on-vs-off, two interleaved runs each: static worker +2.15%, generation p50
+1.8%; moving worker -1.42%, request p50 -2.5%. Within noise. The next round turns the default OFF.
The proven bound and its test are kept for a tighter skip later (smaller or hierarchical blocks,
or a per-cell bound).

Run ledger (from Codex's report): the first build failed on an ambiguous test overload and was
fixed; two timing runs are void because the orchestrator stopped the session so the owner could
use the PC; the eight valid timing runs, the sampler run and the diagnostics runs completed. No
new crash folders. PERF-SAMPLED.md now lists all eight earlier-round UECC crash records.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TaFdXhTdYMkW1xrV6ApT6Y

ARCHITECTURE.md

@@ -580,6 +580,16 @@ driven by `EditorBrush*` props.
   no loads AND no LOD mismatches outstanding.
 - **SDF cache** (`GetDensityWithParams`): search-BOX validity, not chunk-key — gradient ±1
   sampling must not thrash the (expensive) rebuild.
+- **Worm block skip** (`VF_TryGetWormBlockSkip`): inside the unchanged `WormNetworkRange` mask,
+  a worker-local direct-indexed cache covers the mesher's 4×4×4 lattice blocks (including the
+  normal halo). It samples N1 once at the transformed block centre and proves the entire block
+  clears the threshold with the actual 3D hash-gradient field bound
+  `L = (15/4) * sqrt(3) * VOXEL_NOISE_SCALE = 8.118988160`, plus a `1e-3` scaled-output
+  rounding margin. The radius is measured after the exact `WormFrequency`, `VerticalScale`, and
+  `WormHorizontalBias` transform, so anisotropic Z is included. The cache is thread-local and
+  keyed by generator owner, seed, params/layout fingerprint, tile origin, step, lattice size, and
+  worm parameters; malformed/non-lattice/failed proofs fall through. A proof only suppresses N1
+  and N2 because N2 is nonnegative; it never changes `NetworkMask` or density arithmetic.
 - **Operator channel metadata** (`FVoxelOpStack`): `ChannelReads`, `ChannelWrites`, and
   `IsAdditive` are called only when an operator is added to a stack and their values are cached in
   the stack entry. `ValidateChannelOrder` is assembly/diagnostic-only; no declaration virtual may