The editor autosave/load is the single source of truth for what travels
with a scene. Include document-level state (collections, materials) so it
survives reload in every embedder (community cloud save + standalone
localStorage):
- SceneGraph carries optional collections + materials.
- useAutoSave triggers on collections/materials reference changes (not just
nodes) and writes them into the saved graph + the unload flush.
- applySceneGraphToEditor restores them via setScene's extras arg on load.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>