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/editor/src/lib/glb-export.ts

@@ -97,6 +97,18 @@ export function prepareSceneForExport(
   const scene = source.clone(true)
   const cloneByOriginal = pairClones(source, scene)
 
+  // Scans (LiDAR meshes) and guides (floorplan images) are heavy reference
+  // assets stored elsewhere and aren't part of the compiled building. Drop them
+  // from the artifact entirely — `/viewer` re-adds them from the scene graph,
+  // gated by the project's public-visibility flags, so they never bloat the
+  // shared GLB nor slip past those flags into a static public file.
+  for (const [id, original] of sceneRegistry.nodes) {
+    const node = nodes[id]
+    if (node?.type === 'scan' || node?.type === 'guide') {
+      cloneByOriginal.get(original)?.removeFromParent()
+    }
+  }
+
   // Object3Ds that carry node identity — never strip these even when they sit on
   // a non-scene layer. Some are metadata-only: a zone's visible fill/wall meshes
   // are stripped, but its identity node stays to carry the polygon that /viewer