v3.9-Pre-Alpha

Agents could inspect hierarchy parents but could not identify folders, create explorer folders, duplicate objects or remove subtrees through the plugin. Add a bundled rustic-scene-explorer skill and scene_explorer_guide tool, folder/parent support in object_create, folder flags in live/saved inspection, and undoable object_duplicate / object_delete tools using the existing editor document operations.

The skill explains shallow scene organization, actual folder transform semantics, reparenting, shared asset/script references, recursive deletion, undo and saving. Skill installation preserves customized instructions, and the guide tool supplies current guidance on existing installations.

Validation: 140 affected scripting/backend/editor tests passed (one existing ignored test), strict Clippy and formatting passed. Integration coverage includes nested folders, fresh copied IDs and preserved components, sibling/root destinations, recursive deletion/undo/persistence, transparent folder transforms, invalid parents/cycles and pending-review rejection. All nine engine CI checks passed, including the fresh Windows installer build and packaged Setup tests. The Windows engine check passed on retry after an existing Java adapter test exceeded its three-second callback limit.