Finished runs with no output now say so

When a script run finished without writing anything to its log — common for code cells whose result is a rendered control rather than log lines — the activity panel showed "✓ Done" next to a row that still read "Running…", leaving you to guess whether the run had worked.

The log panel now checks the run's actual status: a running activity still shows "Running…", and a finished one with an empty log states "This run produced no output." — in your language.