Register 'shelf' in selection managers (5 arrays + 1 type union)

Shelf renderer was emitting `shelf:click` / `shelf:enter` / `shelf:leave`
via useNodeEvents from the previous commit, but no listener subscribed
— the SelectionManager components (one in editor, one in viewer) each
maintain hardcoded allTypes arrays that didn't include 'shelf'.

Adds 'shelf' to:
- editor/selection-manager: 5 allTypes arrays (one per selection strategy
  — structure, structure-hover, furnish, site, deselect-also-listens-to).
- viewer/selection-manager: the SelectableNodeType union + allTypes
  array.

Shelves can now be clicked / hovered in the 3D canvas and the
selection state updates correctly.

The hardcoded arrays are exactly the kind of cross-cutting friction
the registry is supposed to eliminate. Phase 4 should derive these
lists from `nodeRegistry.entries().filter(d => d.capabilities.selectable)`
so adding a new kind doesn't require editing two files.

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

packages/editor/src/components/editor/selection-manager.tsx

@@ -576,6 +576,7 @@ const SELECTION_STRATEGIES: Record<string, SelectionStrategy> = {
       'roof-segment',
       'stair',
       'stair-segment',
+      'shelf',
       'spawn',
       'window',
       'door',
@@ -1012,6 +1013,7 @@ export const SelectionManager = () => {
       'roof-segment',
       'stair',
       'stair-segment',
+      'shelf',
       'window',
       'door',
       'zone',
@@ -1183,6 +1185,7 @@ export const SelectionManager = () => {
       'roof-segment',
       'stair',
       'stair-segment',
+      'shelf',
       'spawn',
       'window',
       'door',
@@ -1334,6 +1337,7 @@ export const SelectionManager = () => {
       'roof-segment',
       'stair',
       'stair-segment',
+      'shelf',
       'spawn',
       'window',
       'door',
@@ -1408,6 +1412,7 @@ export const SelectionManager = () => {
       'roof-segment',
       'stair',
       'stair-segment',
+      'shelf',
       'spawn',
       'window',
       'door',

packages/viewer/src/components/viewer/selection-manager.tsx

@@ -35,6 +35,7 @@ type SelectableNodeType =
   | 'door'
   | 'column'
   | 'item'
+  | 'shelf'
   | 'slab'
   | 'ceiling'
   | 'roof'
@@ -338,6 +339,7 @@ export const SelectionManager = () => {
       'fence',
       'item',
       'column',
+      'shelf',
       'slab',
       'ceiling',
       'roof',