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/api/src/routes/waitlist.routes.ts

@@ -1,5 +1,12 @@
 import { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify';
 import { prisma } from '@shieldai/db';
+import { EmailService } from '@shieldai/shared-notifications';
+import { Queue } from 'bullmq';
+import { Redis } from 'ioredis';
+
+const redisUrl = process.env.REDIS_URL || 'redis://localhost:6379';
+const connection = new Redis(redisUrl);
+const waitlistEmailQueue = new Queue('waitlist-emails', { connection });
 
 interface WaitlistSignupBody {
   email: string;
@@ -10,6 +17,13 @@ interface WaitlistSignupBody {
   utmCampaign?: string;
 }
 
+function getPosition(entryId: string): string {
+  const hash = entryId.split('').reduce((acc, c) => acc + c.charCodeAt(0), 0);
+  return String(10000 + (hash % 90000));
+}
+
+const DAY_MS = 24 * 60 * 60 * 1000;
+
 export async function waitlistRoutes(fastify: FastifyInstance) {
   fastify.post('/waitlist/signup', async (request: FastifyRequest, reply: FastifyReply) => {
     const body = request.body as WaitlistSignupBody;
@@ -48,6 +62,47 @@ export async function waitlistRoutes(fastify: FastifyInstance) {
       },
     });
 
+    const name = body.name?.trim() || 'there';
+    const position = getPosition(entry.id);
+
+    try {
+      const emailService = EmailService.getInstance();
+      const result = await emailService.sendWithTemplate(email, {
+        templateId: 'waitlist_confirmation',
+        variables: { name, position },
+      });
+      if (result.status === 'failed') {
+        request.log.warn({ error: result.error }, 'Failed to send waitlist confirmation email');
+      } else {
+        request.log.info({ email }, 'Waitlist confirmation email sent');
+      }
+    } catch (err) {
+      request.log.error({ err }, 'Error sending waitlist confirmation email');
+    }
+
+    try {
+      await Promise.all([
+        waitlistEmailQueue.add(
+          'send-waitlist-intro',
+          { email, name, entryId: entry.id, tier },
+          { delay: 1 * DAY_MS, attempts: 3, backoff: { type: 'exponential', delay: 5000 } }
+        ),
+        waitlistEmailQueue.add(
+          'send-waitlist-features',
+          { email, name, entryId: entry.id, tier },
+          { delay: 3 * DAY_MS, attempts: 3, backoff: { type: 'exponential', delay: 5000 } }
+        ),
+        waitlistEmailQueue.add(
+          'send-waitlist-launch-teaser',
+          { email, name, entryId: entry.id, tier },
+          { delay: 7 * DAY_MS, attempts: 3, backoff: { type: 'exponential', delay: 5000 } }
+        ),
+      ]);
+      request.log.info({ email }, 'Welcome sequence scheduled');
+    } catch (err) {
+      request.log.error({ err }, 'Failed to schedule welcome sequence emails');
+    }
+
     return reply.code(201).send({
       message: 'Welcome to the ShieldAI waitlist',
       id: entry.id,