A cross clicked in the frame its task ended no longer puts "no task N"
in the status bar: the row's cancel goes to the engine directly instead
of through the app's command runner, which reports every error there.
The face-scan row test scans demo photos no other scan test uses, so it
no longer joins the scan deadlock of #630 (with one of the existing pump
tests it hung 13 of 20 runs; now 0 of 20).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>