Checkout fixes that win back sales

1. Show the total price, delivery cost and delivery date before checkout.
2. Offer guest checkout. Accounts can come after the first order.
3. Keep the form short: name, phone, address. Ask for the rest later.
4. Show trust signals near the pay button: returns, secure payment, cash on delivery.
5. Test the whole flow on a cheap Android phone, not only on your laptop.