FRE-5335 Hook waitlist signup to send confirmation email via Resend

- Added @shieldai/shared-notifications, bullmq, ioredis deps to API
- POST /api/waitlist/signup now sends waitlist_confirmation email via EmailService
- Schedules welcome sequence (day1 intro, day3 features, day7 launch teaser) via BullMQ delayed jobs
- Added waitlist email worker in @shieldai/jobs to process delayed welcome sequence emails
- Templates already in place: waitlist_confirmation, waitlist_intro, waitlist_features, waitlist_launch_teaser with dark-themed HTML layouts

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/jobs/src/index.ts

@@ -134,6 +134,47 @@ export async function scheduleWebhookProcessor() {
   });
 }
 
+// Waitlist email worker
+import { EmailService } from '@shieldai/shared-notifications';
+
+const waitlistEmailWorker = new Worker(
+  "waitlist-emails",
+  async (job) => {
+    const { email, name, entryId } = job.data;
+    const templateIdMap: Record<string, string> = {
+      'send-waitlist-intro': 'waitlist_intro',
+      'send-waitlist-features': 'waitlist_features',
+      'send-waitlist-launch-teaser': 'waitlist_launch_teaser',
+    };
+
+    const templateId = templateIdMap[job.name];
+    if (!templateId) {
+      throw new Error(`Unknown waitlist email job: ${job.name}`);
+    }
+
+    const emailService = EmailService.getInstance();
+    const result = await emailService.sendWithTemplate(email, {
+      templateId,
+      variables: { name, entryId },
+    });
+
+    if (result.status === 'failed') {
+      throw new Error(`Failed to send ${templateId} to ${email}: ${result.error}`);
+    }
+
+    return { templateId, email, deliveredAt: result.deliveredAt };
+  },
+  { connection, concurrency: 5 }
+);
+
+waitlistEmailWorker.on("completed", (job) => {
+  console.log(`[WaitlistEmail] Job ${job?.id} (${job?.name}) completed for ${job?.data?.email}`);
+});
+
+waitlistEmailWorker.on("failed", (job, err) => {
+  console.error(`[WaitlistEmail] Job ${job?.id} (${job?.name}) failed: ${err.message}`);
+});
+
 console.log("Job workers started");
 
 // Report generation workers