Managers and superusers were silently filtered to only their own
submitted POs because submitterId: userId was applied unconditionally.
Submitters were also shown MGR_APPROVED, SENT_FOR_PAYMENT,
PAID_DELIVERED and REJECTED orders alongside CLOSED ones.
Fix: managers/superusers see all CLOSED POs (no submitterId filter);
submitters see only their own CLOSED POs.
Fixes#6
