Redesign create invoice modal

ui/app/(app)/dashboard/actions.ts

@@ -77,12 +77,12 @@ export async function createInvoiceAction(
   const isFiat = amountMode === "fiat";
   const instantConfirmation = formData.get("instant_confirmation") === "1";
   const confirmationRaw = String(formData.get("confirmation_target") ?? "").trim();
-  const confirmationTarget = instantConfirmation ? 0 : Number(confirmationRaw);
-  if (
-    Number.isNaN(confirmationTarget) ||
-    confirmationTarget < 0 ||
-    confirmationTarget > 10
-  ) {
+  let confirmationTarget: number | null = null;
+  if (instantConfirmation) {
+    confirmationTarget = 0;
+  } else if (confirmationRaw) {
+    const parsed = Number(confirmationRaw);
+    if (Number.isNaN(parsed) || parsed < 0 || parsed > 10) {
       return {
         error: "Confirmation target must be between 0 and 10.",
         invoiceId: null,
@@ -94,6 +94,8 @@ export async function createInvoiceAction(
         warnings: null,
       };
     }
+    confirmationTarget = parsed;
+  }
   const amountRaw = String(
     formData.get(isFiat ? "amount_fiat" : "amount_xmr") ?? ""
   ).trim();
@@ -245,7 +247,7 @@ export async function createInvoiceAction(
       amount_xmr: isFiat ? null : amountRaw,
       amount_fiat: isFiat ? amountRaw : null,
       currency: isFiat ? currency : null,
-      confirmation_target: confirmationTarget,
+      ...(confirmationTarget !== null ? { confirmation_target: confirmationTarget } : {}),
       expires_at: expiresAt,
       checkout_continue_url: checkoutContinueUrlRaw || null,
       metadata: