refactor: replace generateTenantCode boolean with tenantPaymentMethod enum

- Replace generateTenantCode boolean field with tenantPaymentMethod enum ("none" | "iban" | "revolut")
- Update LocationEditForm to use dropdown select instead of toggle for payment method selection
- Consolidate multiple useState hooks into single formValues state object
- Change from defaultValue to controlled components with value/onChange pattern
- Add hidden inputs to preserve tenant data when payment method is not selected
- Update validation logic to check tenantPaymentMethod === "iban"
- Update ViewLocationCard to use new tenantPaymentMethod field
- Add Croatian translations for new dropdown options

This provides better scalability for adding future payment methods and improves form state management.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/ui/ViewLocationCard.tsx

@@ -27,7 +27,7 @@ export const ViewLocationCard:FC<ViewLocationCardProps> = ({location, userSettin
         tenantName,
         tenantStreet,
         tenantTown,
-        generateTenantCode,
+        tenantPaymentMethod,
         // NOTE: only the fileName is projected from the DB to reduce data transfer
         utilBillsProofOfPaymentAttachment,
         utilBillsProofOfPaymentUploadedAt,
@@ -79,7 +79,7 @@ export const ViewLocationCard:FC<ViewLocationCardProps> = ({location, userSettin
 
     const { hub3aText, paymentParams } = useMemo(() => {
 
-        if(!userSettings?.enableIbanPayment || !generateTenantCode) {
+        if(!userSettings?.enableIbanPayment || tenantPaymentMethod !== "iban") {
             return {
                 hub3aText: "",
                 paymentParams: {} as PaymentParams
@@ -126,7 +126,7 @@ export const ViewLocationCard:FC<ViewLocationCardProps> = ({location, userSettin
                     : null
                 }
                 {
-                    userSettings?.enableIbanPayment && generateTenantCode ?
+                    userSettings?.enableIbanPayment && tenantPaymentMethod === "iban" ?
                     <>
                         <p className="max-w-[25em] ml-1 mt-1 mb-1">{t("payment-info-header")}</p>
                         <ul className="ml-4 mb-3">