Add tier-based scan scheduler and webhook triggers (FRE-4498)

- ScanScheduler: tier-based scheduling (BASIC=24h, PLUS=6h, PREMIUM=1h)
- WebhookHandler: HMAC-verified webhook ingestion with SCAN_TRIGGER support
- API routes: /scheduler and /webhooks endpoints under /api/v1/darkwatch
- Jobs: scheduled scan checker + webhook retry processor via BullMQ
- Schema: ScanSchedule, WebhookEvent models; ScanJob.scheduledBy field
- Types: ScheduleStatus, WebhookEventType, WebhookTriggerInput
- Tests: scheduler lifecycle + webhook signature/processing tests

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

packages/shared-notifications/src/services/sms.service.ts

@@ -0,0 +1,82 @@
+import twilio from 'twilio';
+import { loadNotificationConfig } from '../config/notification.config';
+import type { SMSNotification, NotificationResult } from '../types/notification.types';
+
+const config = loadNotificationConfig();
+const twilioClient = twilio(
+  config.twilio.accountSid,
+  config.twilio.authToken
+);
+
+export class SMSService {
+  private static instance: SMSService;
+  private sentCount = new Map<string, number>();
+  private cleanupInterval: NodeJS.Timeout;
+
+  private constructor() {
+    this.cleanupInterval = setInterval(() => {
+      const now = Date.now();
+      for (const [key, timestamp] of this.sentCount.entries()) {
+        if (now - timestamp > 60000) {
+          this.sentCount.delete(key);
+        }
+      }
+    }, 60000);
+  }
+
+  static getInstance(): SMSService {
+    if (!SMSService.instance) {
+      SMSService.instance = new SMSService();
+    }
+    return SMSService.instance;
+  }
+
+  async send(notification: SMSNotification): Promise<NotificationResult> {
+    const rateLimitKey = `sms:${notification.to}`;
+    const currentCount = this.sentCount.get(rateLimitKey) || 0;
+
+    if (currentCount >= config.rateLimits.smsPerMinute) {
+      throw new Error(`SMS rate limit exceeded for ${notification.to}`);
+    }
+
+    try {
+      const message = await twilioClient.messages.create({
+        body: notification.body,
+        from: notification.from || config.twilio.messagingServiceSid,
+        to: notification.to,
+        metadata: notification.metadata,
+      });
+
+      this.sentCount.set(rateLimitKey, currentCount + 1);
+
+      return {
+        notificationId: `sms-${message.sid}`,
+        channel: 'sms',
+        status: 'sent',
+        externalId: message.sid,
+        deliveredAt: new Date(),
+      };
+    } catch (error) {
+      return {
+        notificationId: `sms-${Date.now()}`,
+        channel: 'sms',
+        status: 'failed',
+        error: error instanceof Error ? error.message : 'Unknown error',
+      };
+    }
+  }
+
+  async sendBatch(notifications: SMSNotification[]): Promise<NotificationResult[]> {
+    const results = await Promise.all(
+      notifications.map(n => this.send(n))
+    );
+    return results;
+  }
+
+  getRateLimitStatus(): { remaining: number; limit: number } {
+    return {
+      remaining: config.rateLimits.smsPerMinute - this.sentCount.size,
+      limit: config.rateLimits.smsPerMinute,
+    };
+  }
+}