feat: render OneNote notebook hierarchy

src/onenote/onepkg/joplin-fixture.test.ts

@@ -84,6 +84,23 @@ describe('pinned Joplin .onepkg fixture', () => {
         (section) => section.parseStatus === 'not-requested'
       )
     ).toBe(true);
+    expect(opened.package.tree).toMatchObject({
+      interpreted: true,
+      tocPath: 'Open Notebook.onetoc2',
+      nodes: [
+        { kind: 'section', displayName: 'Tést!' },
+        { kind: 'section', displayName: 'Another section' },
+        {
+          kind: 'section-group',
+          displayName: 'Section group',
+          children: [
+            { kind: 'section', displayName: 'A' },
+            { kind: 'section', displayName: 'B' },
+          ],
+        },
+        { kind: 'section', displayName: '⅀⸨ Unicode ⸩' },
+      ],
+    });
   });
 
   it('opens and parses all five packaged sections end to end', async () => {