docling-rendered tab empty in ui

The docling-rendered tab shows nothing in the UI interface, and this is a very tool to demo docling to people.

IMHO, the docling-ts bindings could also be a bit more verbose (like log something to the console) why it not doing anything.

Start by reproducing the empty docling-rendered tab in the UI, then inspect the docling-ts bindings involved in rendering or reporting errors. Done means the tab displays the expected result and, when it cannot act, the bindings provide a useful console explanation.

Written by the indexing model from the issue text.