Wire shelf + spawn placement polish: SFX, cursor, sidebar, selection

User-visible follow-ups after first running the Phase 2 spike.

Spawn tool now matches legacy UX:
- CursorSphere from @pascal-app/editor for the placement indicator
  (ring + line + tool-icon tooltip) — was a plain sphere mesh.
- Emits sfx:structure-build on commit + setTool(null) + setMode
  ('select') to exit build mode, matching legacy spawn-tool.

Shelf tool placement:
- Emits sfx:structure-build on commit.
- Cursor preview now shows top board + brackets (was just the top),
  matching what gets placed.

Shelf selectable from the 3D canvas:
- ShelfEvent type added to @pascal-app/core/events/bus.
- 'shelf' added to NodeConfig in useNodeEvents.
- ShelfRenderer wires `useNodeEvents(node, 'shelf')` handlers onto
  every mesh. Clicks/hovers now bubble through the editor's selection
  manager and update useViewer.selection.

Shelf appears in the sidebar:
- ShelfTreeNode component (mirrors spawn-tree-node's shape +
  selection/hover/rename wiring; lucide Layers icon).
- TreeNode dispatcher adds a `case 'shelf':` arm.

Framework changes:
- @pascal-app/editor exports CursorSphere alongside triggerSFX.
- @pascal-app/nodes now declares @pascal-app/editor as peer/dev dep.

Pre-existing typecheck errors in @pascal-app/editor (ceiling-tree-node,
fence-tree-node, slab-tree-node, scene.ts) are unchanged — present on
main and not introduced by this commit.

630 tests still pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/editor/src/components/ui/sidebar/panels/site-panel/shelf-tree-node.tsx

@@ -0,0 +1,80 @@
+'use client'
+
+import { type ShelfNode, useScene } from '@pascal-app/core'
+import { useViewer } from '@pascal-app/viewer'
+import { Layers } from 'lucide-react'
+import { memo, useCallback, useState } from 'react'
+import useEditor from './../../../../../store/use-editor'
+import { InlineRenameInput } from './inline-rename-input'
+import { focusTreeNode, handleTreeSelection, TreeNodeWrapper } from './tree-node'
+import { TreeNodeActions } from './tree-node-actions'
+
+interface ShelfTreeNodeProps {
+  nodeId: ShelfNode['id']
+  depth: number
+  isLast?: boolean
+}
+
+/**
+ * Sidebar tree entry for shelf. Mirrors spawn-tree-node's shape so the
+ * existing tree-node-wrapper / selection / hover / rename plumbing all work
+ * unchanged. Phase 4 derives this row generically from
+ * `definition.presentation` — until then, one file per kind.
+ */
+export const ShelfTreeNode = memo(function ShelfTreeNode({
+  nodeId,
+  depth,
+  isLast,
+}: ShelfTreeNodeProps) {
+  const [isEditing, setIsEditing] = useState(false)
+  const isVisible = useScene((s) => s.nodes[nodeId]?.visible !== false)
+  const isSelected = useViewer((state) => state.selection.selectedIds.includes(nodeId))
+  const isHovered = useViewer((state) => state.hoveredId === nodeId)
+  const setSelection = useViewer((state) => state.setSelection)
+  const setHoveredId = useViewer((state) => state.setHoveredId)
+
+  const handleClick = useCallback(
+    (e: React.MouseEvent) => {
+      e.stopPropagation()
+      const handled = handleTreeSelection(
+        e,
+        nodeId,
+        useViewer.getState().selection.selectedIds,
+        setSelection,
+      )
+      if (!handled && useEditor.getState().phase === 'furnish') {
+        useEditor.getState().setPhase('structure')
+      }
+    },
+    [nodeId, setSelection],
+  )
+
+  return (
+    <TreeNodeWrapper
+      actions={<TreeNodeActions nodeId={nodeId} />}
+      depth={depth}
+      expanded={false}
+      hasChildren={false}
+      icon={<Layers size={14} />}
+      isHovered={isHovered}
+      isLast={isLast}
+      isSelected={isSelected}
+      isVisible={isVisible}
+      label={
+        <InlineRenameInput
+          defaultName="Shelf"
+          isEditing={isEditing}
+          nodeId={nodeId}
+          onStartEditing={() => setIsEditing(true)}
+          onStopEditing={() => setIsEditing(false)}
+        />
+      }
+      nodeId={nodeId}
+      onClick={handleClick}
+      onDoubleClick={() => focusTreeNode(nodeId)}
+      onMouseEnter={() => setHoveredId(nodeId)}
+      onMouseLeave={() => setHoveredId(null)}
+      onToggle={() => {}}
+    />
+  )
+})

packages/editor/src/components/ui/sidebar/panels/site-panel/tree-node.tsx

@@ -63,6 +63,7 @@ import { FenceTreeNode } from './fence-tree-node'
 import { ItemTreeNode } from './item-tree-node'
 import { LevelTreeNode } from './level-tree-node'
 import { RoofTreeNode } from './roof-tree-node'
+import { ShelfTreeNode } from './shelf-tree-node'
 import { SlabTreeNode } from './slab-tree-node'
 import { SpawnTreeNode } from './spawn-tree-node'
 import { StairTreeNode } from './stair-tree-node'
@@ -94,6 +95,8 @@ export const TreeNode = memo(function TreeNode({ nodeId, depth = 0, isLast }: Tr
       return <ElevatorTreeNode depth={depth} isLast={isLast} nodeId={nodeId} />
     case 'level':
       return <LevelTreeNode depth={depth} isLast={isLast} nodeId={nodeId as `level_${string}`} />
+    case 'shelf':
+      return <ShelfTreeNode depth={depth} isLast={isLast} nodeId={nodeId as `shelf_${string}`} />
     case 'slab':
       return <SlabTreeNode depth={depth} isLast={isLast} nodeId={nodeId} />
     case 'spawn':

packages/editor/src/index.tsx

@@ -4,6 +4,7 @@ export {
   type SnapshotCameraData,
   ThumbnailGenerator,
 } from './components/editor/thumbnail-generator'
+export { CursorSphere } from './components/tools/shared/cursor-sphere'
 export { CameraActions as ViewerToolbarRight } from './components/ui/action-menu/camera-actions'
 export { ViewToggles as ViewerToolbarLeft } from './components/ui/action-menu/view-toggles'
 export { useCommandPalette } from './components/ui/command-palette'