feat(viewer): strip scans/guides from the bake, re-add from scene data

Scans (LiDAR meshes) and guides (floorplan images) are heavy reference assets
stored elsewhere, not part of the compiled building — and baking them into a
public static GLB would also bypass the per-project show_*_public flags. Strip
both from the export entirely (previously they leaked in as empty identity
nodes, timing-dependent).

The GLB viewer re-adds them at runtime from the scene graph, like lights:
GlbReferenceNodes resolves each scan/guide's registry renderer (no static nodes
import — same nodeRegistry path the viewer already uses) and portals it into its
parent level's baked node, so the node's level-local transform resolves to the
right world pose and rides level stacking. Uses the same GuideRenderer/
ScanRenderer + asset resolver as the parametric viewer, so http-backed assets
show for everyone and local asset:// ones for the owner — exact parity.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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

@@ -8,7 +8,7 @@ import { ParametricNodeRenderer } from './parametric-node-renderer'
 // on every render — that would create a new Suspense boundary each time.
 const lazyCache = new WeakMap<RendererSource<AnyNode>, ComponentType<{ node: AnyNode }>>()
 
-function getRegistryRenderer(
+export function getRegistryRenderer(
   source: RendererSource<AnyNode>,
 ): ComponentType<{ node: AnyNode }> | null {
   const cached = lazyCache.get(source)