Feat/stairs fence update (#226)

* feat: railing on the straight stairs and new fence

* feat: added spiral and curved stairs with bug fix for fence

* feat:fence are linked to each other ... so moving one move the other sharing the same coordinate

* fix: update stair railing logic to include front-side attachments for terminal landings

* Integrate fence rendering into the fence system

* fix: pass nodeId instead of undefined node to WallTreeNode and FenceTreeNode

TreeNode was passing `node` (undefined variable) instead of `nodeId` to
WallTreeNode and FenceTreeNode, causing a runtime ReferenceError.
Updated FenceTreeNode to accept nodeId and look up the node from the
scene store internally, consistent with all other tree node components.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: update fence icon with new isometric design

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Aymeric Rabot <aymeric@pascal.app>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

packages/viewer/src/components/renderers/node-renderer.tsx

@@ -4,6 +4,7 @@ import { type AnyNode, useScene } from '@pascal-app/core'
 import { BuildingRenderer } from './building/building-renderer'
 import { CeilingRenderer } from './ceiling/ceiling-renderer'
 import { DoorRenderer } from './door/door-renderer'
+import { FenceRenderer } from './fence/fence-renderer'
 import { GuideRenderer } from './guide/guide-renderer'
 import { ItemRenderer } from './item/item-renderer'
 import { LevelRenderer } from './level/level-renderer'
@@ -32,6 +33,7 @@ export const NodeRenderer = ({ nodeId }: { nodeId: AnyNode['id'] }) => {
       {node.type === 'item' && <ItemRenderer node={node} />}
       {node.type === 'slab' && <SlabRenderer node={node} />}
       {node.type === 'wall' && <WallRenderer node={node} />}
+      {node.type === 'fence' && <FenceRenderer node={node} />}
       {node.type === 'door' && <DoorRenderer node={node} />}
       {node.type === 'window' && <WindowRenderer node={node} />}
       {node.type === 'zone' && <ZoneRenderer node={node} />}