Breadcrumb polishing

[priethor]

What

Part of #96

Two breadcrumb fixes from #53.

• Breadcrumb waits for the canvas to finish switching pages instead of jumping ahead.
• Page titles use the raw title, so A & B no longer shows as A & B.

Testing

1. Rename a page to A & B and confirm the breadcrumb renders it correctly.
2. Type unsaved text in a page, then switch pages from the sidebar.
3. Confirm the breadcrumb changes only when the editor switches to the new page.