Cover access on GET and POST for a buyer, each required field when blank, an ETD
after the ETA, a batch that already has a shipment (queried, not blocked), a
status change, and an edit updating in place. Add the shipment routes to both
OPS_ROUTES sweeps so the detail and edit screens render clean markup, and assert
the native date inputs carry ISO values — the defect that left the intake and
batch edit dates blank.
