feat: add public product catalog boundary

packages/contracts/public-product.js

@@ -0,0 +1,20 @@
+function toIsoString(value) {
+  return value instanceof Date ? value.toISOString() : value;
+}
+
+export function toPublicProductDto(product) {
+  return {
+    id: product.id,
+    categoryId: product.categoryId,
+    name: product.name,
+    slug: product.slug,
+    description: product.description ?? null,
+    brand: product.brand ?? null,
+    setName: product.setName ?? null,
+    cardNumber: product.cardNumber ?? null,
+    eventName: product.eventName ?? null,
+    releaseYear: product.releaseYear ?? null,
+    createdAt: toIsoString(product.createdAt),
+    updatedAt: toIsoString(product.updatedAt),
+  };
+}