fix(site-builder): reattach unreachable nodes when loading a page

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

craft/src/state/PageContext.orphan-repair.test.ts

@@ -0,0 +1,43 @@
+import { describe, test, expect } from 'vitest';
+import { renderEditorHarness } from '../test-utils/editorHarness';
+import { repairOrphanNodes } from '../utils/orphan-repair';
+import { EMPTY_CANVAS } from './PageContext';
+
+describe('EMPTY_CANVAS is exported and loadable', () => {
+  test('deserializing EMPTY_CANVAS gives a ROOT with no children', () => {
+    const harness = renderEditorHarness({ initialState: EMPTY_CANVAS });
+    const nodes = JSON.parse(harness.getSerialized());
+    expect(nodes.ROOT.nodes).toEqual([]);
+    harness.unmount();
+  });
+});
+
+describe('repaired state survives a real Craft deserialize', () => {
+  test('an orphaned HTML block becomes a selectable child of ROOT', () => {
+    const broken = JSON.stringify({
+      ROOT: {
+        type: { resolvedName: 'Container' },
+        isCanvas: true,
+        props: { style: {}, tag: 'div' },
+        displayName: 'Container',
+        custom: {}, hidden: false, nodes: [], linkedNodes: {}, parent: null,
+      },
+      stray: {
+        type: { resolvedName: 'HtmlBlock' },
+        isCanvas: false,
+        props: { code: '<p>stranded</p>', style: {} },
+        displayName: 'HTML',
+        custom: {}, hidden: false, nodes: [], linkedNodes: {}, parent: 'ghost',
+      },
+    });
+
+    const { state, repaired } = repairOrphanNodes(broken);
+    expect(repaired).toEqual(['stray']);
+
+    const harness = renderEditorHarness({ initialState: state });
+    const nodes = JSON.parse(harness.getSerialized());
+    expect(nodes.ROOT.nodes).toContain('stray');
+    expect(harness.container.textContent).toContain('stranded');
+    harness.unmount();
+  });
+});