Selection: registry-driven, drop spawn flag, restore green color

Two concerns from the spike:

1) Selection / floating-action-menu had hardcoded kind lists scattered
   across 4 files. Adding 'shelf' to each one per migration was the
   wrong abstraction — the user's question "did you make it generic
   from the noderegistry?" was the right one. Done now.

   Added to @pascal-app/core/registry:
   - getSelectableKinds(): string[] — returns all registered kinds
     whose definition declares `capabilities.selectable`.
   - isRegistrySelectable(kind): boolean — predicate for OR-chains.

   Refactored hardcoded sites to merge registry kinds at runtime,
   keeping legacy hardcoded lists intact so existing kinds keep
   working unchanged:
   - editor SelectionManager: 4 subscription loops (enter/leave/click)
     + structure.isValid + getSelectionTarget — all augment with
     registry kinds. Phase 6 deletes the hardcoded lists.
   - viewer SelectionManager: subscription loop + SelectableNodeType
     broadened with `(string & {})` to accept registry kinds.
   - floating-action-menu: ALLOWED_TYPES OR'd with isRegistrySelectable.
   - Removed the manually-added 'shelf' entries from previous commit
     857ddd4; they were redundant once the registry-driven path landed.

   Future built-in nodes that declare `capabilities.selectable` get
   click-selection + hover + the floating action menu (move/delete
   icons) for free, no editing of these 4 files.

2) Spawn parity is signed off. Drop the
   NEXT_PUBLIC_USE_REGISTRY_FOR_SPAWN flag entirely; spawn registers
   unconditionally in builtinPlugin.nodes. Restored SPAWN_COLOR to
   the original #22c55e green (was #ef4444 red as a Phase 2
   verification marker).

Pre-existing typecheck errors in editor (ceiling/fence/slab tree-node,
scene.ts buildingId) are unchanged.

630 tests still pass.

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

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

@@ -6,6 +6,7 @@ import {
   type BuildingNode,
   type ColumnNode,
   emitter,
+  getSelectableKinds,
   type ItemNode,
   type LevelNode,
   type NodeEvent,
@@ -25,6 +26,10 @@ const tempWorldPos = new Vector3()
 // Tolerance for edge detection (in meters)
 const EDGE_TOLERANCE = 0.5
 
+// Hardcoded kinds the viewer's selection manager knows about. Registry kinds
+// (any NodeDefinition with `capabilities.selectable`) are merged in at
+// runtime via getSelectableKinds() — Phase 6 collapses this into a single
+// registry-driven list.
 type SelectableNodeType =
   | 'building'
   | 'level'
@@ -35,11 +40,11 @@ type SelectableNodeType =
   | 'door'
   | 'column'
   | 'item'
-  | 'shelf'
   | 'slab'
   | 'ceiling'
   | 'roof'
   | 'roof-segment'
+  | (string & {})
 
 // Expand polygon outward by a small amount to include items on edges
 const expandPolygon = (polygon: [number, number][], tolerance: number): [number, number][] => {
@@ -330,7 +335,9 @@ export const SelectionManager = () => {
       useViewer.setState({ hoveredId: null })
     }
 
-    // Subscribe to all node types
+    // Subscribe to all node types. Hardcoded kinds + registry-supplied kinds
+    // (any NodeDefinition declaring `capabilities.selectable`). Phase 6
+    // collapses these into a single registry-driven list.
     const allTypes: SelectableNodeType[] = [
       'building',
       'level',
@@ -339,7 +346,6 @@ export const SelectionManager = () => {
       'fence',
       'item',
       'column',
-      'shelf',
       'slab',
       'ceiling',
       'roof',
@@ -347,17 +353,22 @@ export const SelectionManager = () => {
       'window',
       'door',
     ]
-    for (const type of allTypes) {
-      emitter.on(`${type}:enter`, onEnter)
-      emitter.on(`${type}:leave`, onLeave)
-      emitter.on(`${type}:click`, onClick)
+    const registryKinds = getSelectableKinds().filter(
+      (k) => !(allTypes as readonly string[]).includes(k),
+    ) as SelectableNodeType[]
+    const subscribedKinds = [...allTypes, ...registryKinds]
+
+    for (const type of subscribedKinds) {
+      emitter.on(`${type}:enter` as any, onEnter as any)
+      emitter.on(`${type}:leave` as any, onLeave as any)
+      emitter.on(`${type}:click` as any, onClick as any)
     }
 
     return () => {
-      for (const type of allTypes) {
-        emitter.off(`${type}:enter`, onEnter)
-        emitter.off(`${type}:leave`, onLeave)
-        emitter.off(`${type}:click`, onClick)
+      for (const type of subscribedKinds) {
+        emitter.off(`${type}:enter` as any, onEnter as any)
+        emitter.off(`${type}:leave` as any, onLeave as any)
+        emitter.off(`${type}:click` as any, onClick as any)
       }
     }
   }, [])