First real-hardware test revealed the connected dashcam's SD card ships
factory-formatted with no partition table - lsblk reports it as a bare
"disk" with an fstype set directly, never as a child "part". The
previous detection logic only matched type=="part", so it silently
missed this real device entirely.
list_usb_storage_partitions() now also matches whole-disk USB devices
that have no children and an fstype set directly on them, in addition
to the existing partition-table case. Verified against a fixture built
from this dashcam's actual `lsblk -J` output.
Co-authored-by: Copilot <[email protected]>
