render: extract WMO scene instance factory

Work-Package: M03-RND-WMO-SCENE-INSTANCE-FACTORY-001
Agent: sindo-main-codex
Tests: 65/66 headless verifiers; proprietary ADT probe unavailable; checkpoint dry-run 7/7; docs and coordination passed
Fidelity: valid cached/live naming, placement, validation and Resource identity preserved; invalid-root leak fixed

RENDER.md

@@ -1491,6 +1491,18 @@ $exe = Join-Path $env:TEMP 'godot-4.6.1-openwc\Godot_v4.6.1-stable_win64.exe'
   queues and permits remain loader-owned. Synthetic traversal timing is not
   private-asset visual, leak, GPU or p95/p99 evidence.
 
+## 2026-08-01 WMO Scene Instance Factory Extraction
+
+- `WmoSceneInstanceFactory` now owns cached PackedScene instantiation/currentness
+  validation and live-prototype duplication with shared basename/placement rules.
+- Cached validation still precedes placement; live duplicates still skip the
+  scene-cache validator. Accepted descendant Resources retain exact identity.
+- Invalid non-Node3D cached roots are now freed synchronously, closing an
+  error-path lifetime leak that normal scene-cache admission already prevents.
+- Source lookup, ResourceLoader, runtime preparation, attachment, registry,
+  queues and permits remain loader-owned. Synthetic factory timing is not
+  private-asset visual, leak/GPU or p95/p99 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.