fix(invoices): show "Draft" on the invoice detail page for accumulator drafts

Follow-up to the Bills-list change: the invoice detail header still printed
"Scheduled" for a running monthly/manual draft (is_monthly_draft). It already
had a separate monthly-draft badge, but the status pill itself now reads
"Draft" too, matching the list and the Billed-chip link target.

frontend/src/pages/admin/bills/BillDetailPage.tsx

@@ -264,7 +264,10 @@ export const BillDetailPage: React.FC = () => {
               </span>
             )}
             <span className="ml-2 text-xs font-medium px-2 py-0.5 rounded bg-neutral-100 text-neutral-700">
-              {t(`bills.status.${inv.status}`, inv.status)}
+              {/* A running monthly/manual accumulator carries status
+                  'scheduled' but never auto-sends on manual cadence —
+                  read it as "Draft", matching the Bills list. */}
+              {inv.isMonthlyDraft ? t('bills.status.draft', 'Draft') : t(`bills.status.${inv.status}`, inv.status)}
             </span>
           </h2>
           <p className="text-sm text-neutral-600 dark:text-neutral-400">