The failure report lives inside the upload modal, but the modal
auto-closed the instant the transfer finished (handleUploadComplete →
onClose), unmounting the report before the user could read it — so the
"which files failed" list never actually appeared.
Split the modal's completion callback in two:
- onUploadComplete: refresh the grid only (no close), as bytes land and
again when processing finishes
- onUploadSettled({ hasFailures }): fired once the transfer settles; the
modal auto-closes only on a clean upload and stays open (report
visible) when any file failed
Also reset the transfer UI when nothing was queued (every file failed),
which previously left the modal spinning forever. Add a PhotoUploadModal
test covering close-on-clean vs stay-open-on-failure.