Partial Refund from Kiosk

Ticket thanh toán từ Kiosk đang lưu db set default Cash discount = % Cash discount của POS

1. Partial refund: chỉ cho phép refund partial ticket từ Kiosk khi Custom fee của POS = Custom fee của Kiosk
2. Case thanh toán không đủ tiền

✅ 1. Full Sale Amount Paid, Tip Not Fully Paid
TotalAmount: $100
PaidAmount: $100
TipAmount: $10
RemainingAmount: $10 (Tip not covered)
Status: Partial (Tip Pending)

❌ 2. Sale Amount Not Fully Paid
TotalAmount: $100
PaidAmount: $80
Remaining Amount: $20 (Sale amount pending)
Status: Partial (Sale Pending)