feat(frontend): add react spa with wishlist flows and public profile

apps/frontend/src/lib/format.ts

@@ -0,0 +1,25 @@
+export function formatPrice(price: string | null | undefined, currency: string): string | null {
+  if (!price) return null;
+  const n = Number(price);
+  if (Number.isNaN(n)) return `${price} ${currency}`;
+  try {
+    return new Intl.NumberFormat(undefined, {
+      style: 'currency',
+      currency,
+      maximumFractionDigits: 2,
+    }).format(n);
+  } catch {
+    return `${n.toLocaleString()} ${currency}`;
+  }
+}
+
+export function formatDate(iso: string | Date): string {
+  const d = typeof iso === 'string' ? new Date(iso) : iso;
+  return d.toLocaleDateString(undefined, { day: 'numeric', month: 'short', year: 'numeric' });
+}
+
+export function daysLeftUntil(iso: string | Date, retentionDays: number): number {
+  const d = typeof iso === 'string' ? new Date(iso) : iso;
+  const expires = d.getTime() + retentionDays * 24 * 60 * 60 * 1000;
+  return Math.max(0, Math.ceil((expires - Date.now()) / (24 * 60 * 60 * 1000)));
+}