Add door check-in flow for Main Tickets

Lets staff redeem a registration's Main Tickets by quantity at the door
(via the Payment/registration flow) instead of scanning each QR code,
and automatically emails/WhatsApps a check-in confirmation to the
attendee. Also routes the At The Door "Open" button and post-payment
flow dynamically: paid registrations jump straight to Check-In instead
of a forced ticket print, since tickets are already sent automatically.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/src/utils/notifications.js

@@ -80,6 +80,17 @@ async function loadRegistrationFull(registrationId) {
   });
 }
 
+async function loadTicketFull(ticketId) {
+  return prisma.ticket.findUnique({
+    where: { id: ticketId },
+    include: {
+      user: { select: { id: true, name: true, email: true, phoneNumber: true, notificationPreference: true } },
+      event: true,
+      registrationOption: { include: { eventOption: true, variant: true } },
+    },
+  });
+}
+
 async function loadPaymentFull(paymentId) {
   return prisma.payment.findUnique({
     where: { id: paymentId },
@@ -488,6 +499,33 @@ function buildPaymentReceipt(payment) {
   return { subject, text, html: emailWrapper(body, { preheader }) };
 }
 
+// ─── Check-in confirmation (Main Tickets, door check-in) ───────────────────────
+
+function buildCheckInConfirmation(ticket, qtyRedeemed, totalRedeemed, remaining) {
+  const org = getOrg();
+  const eventTitle = ticket.event?.title || 'the event';
+  const optionName = ticket.registrationOption?.eventOption?.name || 'Main Ticket';
+  const fullyCheckedIn = remaining <= 0;
+  const subject = `Checked in – ${eventTitle}`;
+  const preheader = `${qtyRedeemed} checked in for ${eventTitle}.`;
+
+  const body = `
+    <p style="font-size:22px;font-weight:800;color:#0f172a;margin:0 0 8px 0;letter-spacing:-0.3px">You're checked in! ✅</p>
+    <p style="font-size:14px;color:#64748b;margin:0 0 32px 0">See you inside</p>
+
+    <p style="margin:0 0 4px 0;color:#374151;font-family:${ff}">Hi <strong>${ticket.user?.name || 'there'}</strong>,</p>
+    <p style="margin:0 0 28px 0;color:#374151;font-family:${ff}">
+      <strong>${qtyRedeemed}</strong> ${optionName}${qtyRedeemed === 1 ? '' : 's'} just checked in for <strong>${eventTitle}</strong>.
+    </p>
+
+    ${callout(`<strong style="font-size:15px">${totalRedeemed} of ${ticket.quantity || 1} checked in</strong>${
+      fullyCheckedIn ? '' : `<br/><span style="font-size:13px">${remaining} remaining on this ticket</span>`
+    }`, fullyCheckedIn ? 'success' : 'info')}`;
+
+  const text = `You're checked in!\n\nHi ${ticket.user?.name || 'there'},\n\n${qtyRedeemed} ${optionName}(s) just checked in for ${eventTitle}.\n\n${totalRedeemed} of ${ticket.quantity || 1} checked in${fullyCheckedIn ? '' : `, ${remaining} remaining`}.\n\n${org.name} — ${org.email}`;
+  return { subject, text, html: emailWrapper(body, { preheader }) };
+}
+
 // ─── Donation applied to a registration ────────────────────────────────────────
 //
 // Distinct from buildPaymentReceipt: this is sent to the REGISTRANT when staff apply
@@ -893,6 +931,32 @@ async function sendRefundEmail(refundPaymentId) {
   }
 }
 
+async function sendCheckInEmails(ticketId, qtyRedeemed, totalRedeemed, remaining) {
+  try {
+    const ticket = await loadTicketFull(ticketId);
+    if (!ticket) return;
+    const user = ticket.user;
+    const { shouldEmail, waText, waTextAny } = require('./notify');
+    const { buildWACheckIn } = require('./waMessages');
+
+    const sends = [];
+    const hasValidEmail = user?.email && !user.email.endsWith('@guest.local') && !user.email.endsWith('@deleted.invalid');
+    if (hasValidEmail && shouldEmail(user)) {
+      const msg = buildCheckInConfirmation(ticket, qtyRedeemed, totalRedeemed, remaining);
+      sends.push(sendMail({ to: user.email, subject: msg.subject, html: msg.html, text: msg.text }));
+    }
+    const waMsg = buildWACheckIn(ticket, qtyRedeemed, totalRedeemed, remaining);
+    if (hasValidEmail) {
+      sends.push(waText(user, waMsg));
+    } else {
+      sends.push(waTextAny(user, waMsg));
+    }
+    await Promise.all(sends);
+  } catch (e) {
+    console.error('Failed to send check-in emails:', e);
+  }
+}
+
 // Sent when staff apply a donation to someone's registration. Only the registrant is
 // notified (anonymously, per design) — the donor already received their donation-received
 // notification when the donation was originally made, so they are deliberately not emailed
@@ -981,4 +1045,6 @@ module.exports = {
   sendRefundEmail,
   sendSelfServiceRegistrationEmails,
   sendDonationAssignmentEmails,
+  sendCheckInEmails,
+  buildCheckInConfirmation,
 };