The degradation guard in crawl() wrapped only chromium.launch(), while
the driver start sat outside it in the async context manager. A failure
to start the driver therefore propagated out of crawl() and failed the
whole DeepSearch job, contradicting the warning it logs on that path
("pages will use httpx only").
Start the driver inside the guarded block and stop it in the finally, so
an unavailable driver degrades to httpx-only fetching as intended. The
crawl loop body is unchanged apart from indentation.