GetPosDashboardQuery payment breakdown SQL was grouping by
order_statuses.name (e.g. "Completed") instead of orders.payment_method
(e.g. "cash", "card", "qr", "transfer").
Fix: GROUP BY o.payment_method with COALESCE for empty values.
Frontend: apply MapPaymentMethodLabel() to translate method names
to Vietnamese (Tiền mặt, Thẻ, Mã QR, Chuyển khoản).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>