feat(emails): render event reminders in event displayTimezone

Registration, waitlist, and series-pass confirmation emails formatted
dates with Intl.DateTimeFormat in the server's local TZ. Switch to
event.displayTimezone (fallback America/Toronto) so the email shows
the event's intended wall-clock + zone suffix regardless of where the
Resend worker runs.

Inline formatters in three exports collapsed to two module-level
helpers that take a timeZone argument.

server/utils/resend.js

@@ -2,6 +2,29 @@ import { Resend } from "resend";
 
 const resend = new Resend(useRuntimeConfig().resendApiKey);
 
+const formatEventDate = (dateString, timeZone = "America/Toronto") => {
+  const date = new Date(dateString);
+  return new Intl.DateTimeFormat("en-US", {
+    weekday: "long",
+    year: "numeric",
+    month: "long",
+    day: "numeric",
+    timeZone,
+  }).format(date);
+};
+
+const formatEventTime = (startDate, endDate, timeZone = "America/Toronto") => {
+  const start = new Date(startDate);
+  const end = new Date(endDate);
+  const timeFormat = new Intl.DateTimeFormat("en-US", {
+    hour: "numeric",
+    minute: "2-digit",
+    timeZoneName: "short",
+    timeZone,
+  });
+  return `${timeFormat.format(start)} - ${timeFormat.format(end)}`;
+};
+
 /**
  * Send event registration confirmation email
  * @param {Object} options - { requiresSignIn?: boolean } — when true, appends a
@@ -9,29 +32,7 @@ const resend = new Resend(useRuntimeConfig().resendApiKey);
  *   registered via the public form and did not receive an auto-login cookie.
  */
 export async function sendEventRegistrationEmail(registration, eventData, options = {}) {
-  const formatDate = (dateString) => {
+  const tz = eventData.displayTimezone || "America/Toronto";
-    const date = new Date(dateString);
-    return new Intl.DateTimeFormat("en-US", {
-      weekday: "long",
-      year: "numeric",
-      month: "long",
-      day: "numeric",
-    }).format(date);
-  };
-
-  const formatTime = (startDate, endDate) => {
-    const start = new Date(startDate);
-    const end = new Date(endDate);
-
-    const timeFormat = new Intl.DateTimeFormat("en-US", {
-      hour: "numeric",
-      minute: "2-digit",
-      timeZoneName: "short",
-    });
-
-    return `${timeFormat.format(start)} - ${timeFormat.format(end)}`;
-  };
-
   const baseUrl = process.env.BASE_URL || "https://ghostguild.org";
   const eventUrl = `${baseUrl}/events/${eventData.slug || eventData._id}`;
   const signInSection = options.requiresSignIn
@@ -66,8 +67,8 @@ Paid: $${registration.amountPaid.toFixed(2)} CAD`;
 
 You're now registered for ${eventData.title}.
 
-Date: ${formatDate(eventData.startDate)}
+Date: ${formatEventDate(eventData.startDate, tz)}
-Time: ${formatTime(eventData.startDate, eventData.endDate)}
+Time: ${formatEventTime(eventData.startDate, eventData.endDate, tz)}
 Location: ${eventData.location}
 ${eventData.description ? `\n${eventData.description}\n` : ""}${ticketSection}${signInSection}
 View event: ${eventUrl}
@@ -124,29 +125,7 @@ ${baseUrl}/events`,
  * Send waitlist notification email when a spot opens up
  */
 export async function sendWaitlistNotificationEmail(waitlistEntry, eventData) {
-  const formatDate = (dateString) => {
+  const tz = eventData.displayTimezone || "America/Toronto";
-    const date = new Date(dateString);
-    return new Intl.DateTimeFormat("en-US", {
-      weekday: "long",
-      year: "numeric",
-      month: "long",
-      day: "numeric",
-    }).format(date);
-  };
-
-  const formatTime = (startDate, endDate) => {
-    const start = new Date(startDate);
-    const end = new Date(endDate);
-
-    const timeFormat = new Intl.DateTimeFormat("en-US", {
-      hour: "numeric",
-      minute: "2-digit",
-      timeZoneName: "short",
-    });
-
-    return `${timeFormat.format(start)} - ${timeFormat.format(end)}`;
-  };
-
   const baseUrl = process.env.BASE_URL || "https://ghostguild.org";
   const eventUrl = `${baseUrl}/events/${eventData.slug || eventData._id}`;
 
@@ -159,8 +138,8 @@ export async function sendWaitlistNotificationEmail(waitlistEntry, eventData) {
 
 A spot opened up for ${eventData.title}.
 
-Date: ${formatDate(eventData.startDate)}
+Date: ${formatEventDate(eventData.startDate, tz)}
-Time: ${formatTime(eventData.startDate, eventData.endDate)}
+Time: ${formatEventTime(eventData.startDate, eventData.endDate, tz)}
 Location: ${eventData.location}
 
 Register now: ${eventUrl}
@@ -186,29 +165,6 @@ If you can no longer attend, ignore this email and the spot goes to the next per
 export async function sendSeriesPassConfirmation(options) {
   const { to, name, series, ticket, events, paymentId } = options;
 
-  const formatDate = (dateString) => {
-    const date = new Date(dateString);
-    return new Intl.DateTimeFormat("en-US", {
-      weekday: "long",
-      year: "numeric",
-      month: "long",
-      day: "numeric",
-    }).format(date);
-  };
-
-  const formatTime = (startDate, endDate) => {
-    const start = new Date(startDate);
-    const end = new Date(endDate);
-
-    const timeFormat = new Intl.DateTimeFormat("en-US", {
-      hour: "numeric",
-      minute: "2-digit",
-      timeZoneName: "short",
-    });
-
-    return `${timeFormat.format(start)} - ${timeFormat.format(end)}`;
-  };
-
   const formatPrice = (price, currency = "CAD") => {
     if (price === 0) return "Free";
     return new Intl.NumberFormat("en-CA", {
@@ -223,13 +179,13 @@ export async function sendSeriesPassConfirmation(options) {
       : "";
 
   const eventList = events
-    .map(
+    .map((evt, index) => {
-      (evt, index) =>
+      const tz = evt.displayTimezone || "America/Toronto";
-        `  ${index + 1}. ${evt.title}
+      return `  ${index + 1}. ${evt.title}
-     ${formatDate(evt.startDate)}
+     ${formatEventDate(evt.startDate, tz)}
-     ${formatTime(evt.startDate, evt.endDate)}
+     ${formatEventTime(evt.startDate, evt.endDate, tz)}
-     ${evt.location}`,
+     ${evt.location}`;
-    )
+    })
     .join("\n\n");
 
   try {