feat: add Exotel webhook controller and service for call event parsing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/exotel/exotel.service.ts

@@ -0,0 +1,31 @@
+import { Injectable, Logger } from '@nestjs/common';
+import type { ExotelWebhookPayload, CallEvent } from './exotel.types';
+
+@Injectable()
+export class ExotelService {
+    private readonly logger = new Logger(ExotelService.name);
+
+    parseWebhook(payload: ExotelWebhookPayload): CallEvent {
+        const { event_details, call_details } = payload;
+
+        const eventType = event_details.event_type === 'answered' ? 'answered'
+            : event_details.event_type === 'terminal' ? 'ended'
+            : 'ringing';
+
+        const callEvent: CallEvent = {
+            exotelCallSid: call_details.call_sid,
+            eventType,
+            direction: call_details.direction,
+            callerPhone: call_details.customer_details?.number ?? '',
+            agentName: call_details.assigned_agent_details?.name ?? 'Unknown',
+            agentPhone: call_details.assigned_agent_details?.number ?? '',
+            duration: call_details.total_talk_time,
+            recordingUrl: call_details.recordings?.[0]?.url,
+            callStatus: call_details.call_status,
+            timestamp: new Date().toISOString(),
+        };
+
+        this.logger.log(`Parsed Exotel event: ${eventType} for call ${call_details.call_sid}`);
+        return callEvent;
+    }
+}