render: extract WMO render group materializer

Work-Package: M03-RND-WMO-RENDER-GROUP-MATERIALIZER-001
Agent: sindo-main-codex
Tests: 63/64 autonomous verifiers passed; proprietary ADT probe unavailable; baseline dry-run 7/7; documentation and coordination gates passed
Fidelity: exact behavior-preserving node materialization extraction; no new 3.3.5a parity claim

RENDER.md

@@ -1465,6 +1465,19 @@ $exe = Join-Path $env:TEMP 'godot-4.6.1-openwc\Godot_v4.6.1-stable_win64.exe'
   cases and 1,000 current-Mesh calls. This is orchestration extraction, not new
   build-12340 material or visual parity evidence.
 
+## 2026-08-01 WMO Render Group Materializer Extraction
+
+- `WmoRenderGroupMaterializer` now owns creation and single attachment of the
+  lightweight cached WMO `MeshInstance3D` and `MultiMeshInstance3D` groups.
+- Indexed names/transforms, `Group_N`/`DoodadGroup_N` fallbacks, exact
+  Mesh/MultiMesh identity, shadow mode and positive visibility range/margin are
+  unchanged.
+- `StreamingWorldLoader` retains build-step selection, runtime Mesh finalization,
+  queue cursors, permits, optional Editor ownership and placement lifetime.
+- Asset-free verification covers `37` presentation/ownership/source cases and
+  1,000 simple group attachments. This extraction adds no asset-backed GPU,
+  leak, p95/p99 or original-client visual-fidelity evidence.
+
 ## Practical Rule For Future Work
 
 If something improves quality but creates visible hitch, it is not done. Move it to bake/cache/background work, split finalization over frames, or prewarm it before the player can see it.