feat: add 30-day money back guarantee trust badge above complete order button

- Add green trust badge with checkmark icon above 'Complete Order' button
- Add translations for all locales (EN, SR, DE, FR)
- Badge includes: '30-Day Money-Back Guarantee' text
- Styled with green background and border to match trust/conversion theme

src/app/[locale]/checkout/components/PaymentSection.tsx

@@ -38,9 +38,9 @@ export function PaymentSection({
         disabled={disabled}
       />
 
-      {/* Show COD instructions when COD is selected */}
+      {/* COD instructions can be shown here if needed */}
       {selectedMethod?.id === "cod" && (
-        <CODInstructions locale={locale} />
+        <CODInstructions />
       )}
     </section>
   );