fix(io): normalize legacy guide arrays safely

- Restore missing or malformed guides as empty arrays during graph hydration
- Keep library revision clones independent while preserving valid guides

packages/core/src/kiwi/fig/parse/transfer.ts

@@ -1,6 +1,6 @@
 import type { InstanceNodeChange } from '@open-pencil/fig/instance-overrides'
 import { SceneGraph } from '@open-pencil/scene-graph'
-import type { EnabledLibraryBinding } from '@open-pencil/scene-graph'
+import type { EnabledLibraryBinding, SceneNode } from '@open-pencil/scene-graph'
 
 import { getLazyFigImportContext, setLazyFigImportContext } from '#core/kiwi/fig/lazy-import'
 import type { PortableSceneGraphData } from '#core/kiwi/fig/parse/portable-data'
@@ -112,12 +112,14 @@ export function cloneSceneGraphForFigExport(graph: SceneGraph): SceneGraph {
   return cloned
 }
 
+function normalizeNodeGuides(node: SceneNode): SceneNode {
+  return Array.isArray(node.guides) ? node : { ...node, guides: [] }
+}
+
 export function deserializeSceneGraph(data: SerializedSceneGraph): SceneGraph {
   const graph = new SceneGraph()
   graph.rootId = data.rootId
-  graph.nodes = new Map(
-    data.nodes.map(([id, node]) => [id, { ...node, guides: node.guides ?? [] }])
-  )
+  graph.nodes = new Map(data.nodes.map(([id, node]) => [id, normalizeNodeGuides(node)]))
   graph.images = new Map(data.images)
   graph.variables = new Map(data.variables)
   graph.variableCollections = new Map(data.variableCollections)

packages/core/src/library/serialization.ts

@@ -1,4 +1,5 @@
 import { SceneGraph } from '@open-pencil/scene-graph'
+import type { SceneNode } from '@open-pencil/scene-graph'
 
 import type { PortableSceneGraphData } from '#core/kiwi/fig/parse/portable-data'
 
@@ -34,18 +35,17 @@ export function serializeLibraryRevision(
   }
 }
 
+function cloneLibraryNode(node: SceneNode): SceneNode {
+  const cloned = structuredClone(node)
+  return Array.isArray(cloned.guides) ? cloned : { ...cloned, guides: [] }
+}
+
 export function deserializeLibraryRevision(
   revision: SerializedComponentLibraryRevision
 ): ComponentLibraryRevision {
   const graph = new SceneGraph()
   graph.rootId = revision.graph.rootId
-  graph.nodes = new Map(
-    revision.graph.nodes.map(([id, node]) => {
-      const cloned = structuredClone(node)
-      cloned.guides ??= []
-      return [id, cloned]
-    })
-  )
+  graph.nodes = new Map(revision.graph.nodes.map(([id, node]) => [id, cloneLibraryNode(node)]))
   graph.images = new Map(
     revision.graph.images.map(([hash, bytes]) => [hash, new Uint8Array(bytes)])
   )