feat(registration): add birthdate & postcode

apps/web/src/lib/registration.ts

@@ -29,6 +29,8 @@ export interface GuestEntry {
 	lastName: string;
 	email: string;
 	phone: string;
+	birthdate: string;
+	postcode: string;
 }
 
 export interface GuestErrors {
@@ -36,6 +38,8 @@ export interface GuestErrors {
 	lastName?: string;
 	email?: string;
 	phone?: string;
+	birthdate?: string;
+	postcode?: string;
 }
 
 /**
@@ -52,6 +56,8 @@ export function parseGuests(raw: string | null | undefined): GuestEntry[] {
 			lastName: g.lastName ?? "",
 			email: g.email ?? "",
 			phone: g.phone ?? "",
+			birthdate: g.birthdate ?? "",
+			postcode: g.postcode ?? "",
 		}));
 	} catch {
 		return [];
@@ -87,6 +93,22 @@ export function validatePhone(value: string): string | undefined {
 	return undefined;
 }
 
+export function validateBirthdate(value: string): string | undefined {
+	if (!value.trim()) return "Geboortedatum is verplicht";
+	// Expect YYYY-MM-DD format
+	if (!/^\d{4}-\d{2}-\d{2}$/.test(value))
+		return "Voer een geldige geboortedatum in";
+	const date = new Date(value);
+	if (Number.isNaN(date.getTime())) return "Voer een geldige geboortedatum in";
+	if (date > new Date()) return "Geboortedatum mag niet in de toekomst liggen";
+	return undefined;
+}
+
+export function validatePostcode(value: string): string | undefined {
+	if (!value.trim()) return "Postcode is verplicht";
+	return undefined;
+}
+
 /** Validates all guests and returns errors array + overall validity flag. */
 export function validateGuests(guests: GuestEntry[]): {
 	errors: GuestErrors[];
@@ -103,6 +125,8 @@ export function validateGuests(guests: GuestEntry[]): {
 			g.phone.trim() && !/^[\d\s\-+()]{10,}$/.test(g.phone.replace(/\s/g, ""))
 				? "Voer een geldig telefoonnummer in"
 				: undefined,
+		birthdate: validateBirthdate(g.birthdate),
+		postcode: validatePostcode(g.postcode),
 	}));
 	const valid = !errors.some((e) => Object.values(e).some(Boolean));
 	return { errors, valid };