Booking flow: required terms and privacy checkbox with i18n

Also includes admin, dashboard, and API updates; PWA icon assets; and
assorted layout and utility changes on dev.

frontend/src/lib/api.ts

@@ -179,6 +179,20 @@ export const ticketsApi = {
       method: 'POST',
       body: JSON.stringify(data),
     }),
+
+  guestCreate: (data: {
+    eventId: string;
+    firstName: string;
+    lastName?: string;
+    email?: string;
+    phone?: string;
+    preferredLanguage?: 'en' | 'es';
+    adminNote?: string;
+  }) =>
+    fetchApi<{ ticket: Ticket; payment: Payment; message: string }>('/api/tickets/admin/guest', {
+      method: 'POST',
+      body: JSON.stringify(data),
+    }),
   
   checkPaymentStatus: (ticketId: string) =>
     fetchApi<{ ticketStatus: string; paymentStatus: string; lnbitsStatus?: string; isPaid: boolean }>(
@@ -550,6 +564,7 @@ export interface Ticket {
   checkedInByAdminId?: string;
   qrCode: string;
   adminNote?: string;
+  isGuest?: boolean;
   createdAt: string;
   event?: Event;
   payment?: Payment;

frontend/src/lib/utils.ts

@@ -4,9 +4,14 @@
 // All helpers pin the timezone to America/Asuncion so the output is identical
 // on the server (often UTC) and the client (user's local TZ).  This prevents
 // React hydration mismatches like "07:20 PM" (server) vs "04:20 PM" (client).
+//
+// IMPORTANT — parseDate() must be used instead of raw `new Date(str)` so that
+// ISO-like strings without a timezone suffix (e.g. "2026-04-02T14:00:00") are
+// always treated as UTC.  Without this, the same string produces a different
+// instant on server (Node TZ) vs client (browser / DevTools TZ).
 // ---------------------------------------------------------------------------
 
-const EVENT_TIMEZONE = 'America/Asuncion';
+export const EVENT_TIMEZONE = 'America/Asuncion';
 
 type Locale = 'en' | 'es';
 
@@ -14,11 +19,29 @@ function pickLocale(locale: Locale): string {
   return locale === 'es' ? 'es-ES' : 'en-US';
 }
 
+// Matches ISO-like strings that have NO timezone indicator (Z, +HH:MM, etc.)
+const NAIVE_ISO_RE = /^\d{4}-\d{2}-\d{2}[T ]\d{2}:\d{2}(:\d{2}(\.\d+)?)?$/;
+
+/**
+ * Parse a date string into a deterministic Date object.
+ *
+ * If the string looks like an ISO datetime but lacks a timezone suffix it is
+ * ambiguous — `new Date()` would interpret it in the environment's local
+ * timezone which differs between Node (SSR) and the browser (hydration).
+ * We normalise by appending "Z" so parsing always targets UTC.
+ */
+export function parseDate(dateStr: string): Date {
+  if (NAIVE_ISO_RE.test(dateStr)) {
+    return new Date(dateStr + 'Z');
+  }
+  return new Date(dateStr);
+}
+
 /**
  * "Sat, Feb 14" / "sáb, 14 feb"
  */
 export function formatDateShort(dateStr: string, locale: Locale = 'en'): string {
-  return new Date(dateStr).toLocaleDateString(pickLocale(locale), {
+  return parseDate(dateStr).toLocaleDateString(pickLocale(locale), {
     weekday: 'short',
     month: 'short',
     day: 'numeric',
@@ -30,7 +53,7 @@ export function formatDateShort(dateStr: string, locale: Locale = 'en'): string
  * "Saturday, February 14, 2026" / "sábado, 14 de febrero de 2026"
  */
 export function formatDateLong(dateStr: string, locale: Locale = 'en'): string {
-  return new Date(dateStr).toLocaleDateString(pickLocale(locale), {
+  return parseDate(dateStr).toLocaleDateString(pickLocale(locale), {
     weekday: 'long',
     year: 'numeric',
     month: 'long',
@@ -43,7 +66,7 @@ export function formatDateLong(dateStr: string, locale: Locale = 'en'): string {
  * "February 14, 2026" / "14 de febrero de 2026"  (no weekday)
  */
 export function formatDateMedium(dateStr: string, locale: Locale = 'en'): string {
-  return new Date(dateStr).toLocaleDateString(pickLocale(locale), {
+  return parseDate(dateStr).toLocaleDateString(pickLocale(locale), {
     year: 'numeric',
     month: 'long',
     day: 'numeric',
@@ -55,7 +78,7 @@ export function formatDateMedium(dateStr: string, locale: Locale = 'en'): string
  * "Feb 14, 2026" / "14 feb 2026"
  */
 export function formatDateCompact(dateStr: string, locale: Locale = 'en'): string {
-  return new Date(dateStr).toLocaleDateString(pickLocale(locale), {
+  return parseDate(dateStr).toLocaleDateString(pickLocale(locale), {
     month: 'short',
     day: 'numeric',
     year: 'numeric',
@@ -67,7 +90,7 @@ export function formatDateCompact(dateStr: string, locale: Locale = 'en'): strin
  * "04:30 PM" / "16:30"
  */
 export function formatTime(dateStr: string, locale: Locale = 'en'): string {
-  return new Date(dateStr).toLocaleTimeString(pickLocale(locale), {
+  return parseDate(dateStr).toLocaleTimeString(pickLocale(locale), {
     hour: '2-digit',
     minute: '2-digit',
     timeZone: EVENT_TIMEZONE,
@@ -78,7 +101,7 @@ export function formatTime(dateStr: string, locale: Locale = 'en'): string {
  * "Feb 14, 2026, 04:30 PM" — compact date + time combined
  */
 export function formatDateTime(dateStr: string, locale: Locale = 'en'): string {
-  return new Date(dateStr).toLocaleString(pickLocale(locale), {
+  return parseDate(dateStr).toLocaleString(pickLocale(locale), {
     month: 'short',
     day: 'numeric',
     year: 'numeric',
@@ -92,7 +115,7 @@ export function formatDateTime(dateStr: string, locale: Locale = 'en'): string {
  * "Sat, Feb 14, 04:30 PM" — short date + time combined
  */
 export function formatDateTimeShort(dateStr: string, locale: Locale = 'en'): string {
-  return new Date(dateStr).toLocaleString(pickLocale(locale), {
+  return parseDate(dateStr).toLocaleString(pickLocale(locale), {
     weekday: 'short',
     month: 'short',
     day: 'numeric',