Wire nanoevents-based event bus to the editor core:
- EditorEvents type with render, graph, selection, tool, page, viewport events
- All node mutations (create/update/delete/reparent/reorder) forwarded from SceneGraph
- Selection changes routed through setSelectedIds() with diff detection
- Tool changes routed through setActiveTool() with change detection
- Page switches emit page:changed
- Viewport pan/zoom/fit/zoomTo emit viewport:changed
- Graph replacement emits graph:replaced
- Typed onEditorEvent() subscription on the Editor return object
- useEditorEvent() Vue composable with automatic scope cleanup
- Replace all direct state.selectedIds/state.activeTool mutations in core, app, and SDK
1835903e56