feat: add call events orchestrator with WebSocket gateway, wire Exotel → lookup → enrich → push flow

- CallEventsService orchestrates: Exotel webhook → lead lookup → AI enrichment → WebSocket push
- CallEventsGateway (Socket.IO /call-events namespace) with agent room registration and disposition handling
- EnrichedCallEvent/DispositionPayload types for frontend contract
- Disposition flow: creates Call record, updates lead status, logs lead activity
- Wired ExotelController to forward answered/ended events to CallEventsService
- forwardRef used to resolve circular dependency between gateway and service

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/exotel/exotel.controller.ts

@@ -1,12 +1,16 @@
 import { Controller, Post, Body, Logger, HttpCode } from '@nestjs/common';
 import { ExotelService } from './exotel.service';
+import { CallEventsService } from '../call-events/call-events.service';
 import type { ExotelWebhookPayload } from './exotel.types';
 
 @Controller('webhooks/exotel')
 export class ExotelController {
     private readonly logger = new Logger(ExotelController.name);
 
-    constructor(private readonly exotelService: ExotelService) {}
+    constructor(
+        private readonly exotelService: ExotelService,
+        private readonly callEventsService: CallEventsService,
+    ) {}
 
     @Post('call-status')
     @HttpCode(200)
@@ -15,9 +19,11 @@ export class ExotelController {
 
         const callEvent = this.exotelService.parseWebhook(payload);
 
-        // TODO: Forward to CallEventsService (Task 4)
-        // For now, just log
-        this.logger.log(`Call event: ${JSON.stringify(callEvent)}`);
+        if (callEvent.eventType === 'answered') {
+            await this.callEventsService.handleIncomingCall(callEvent);
+        } else if (callEvent.eventType === 'ended') {
+            await this.callEventsService.handleCallEnded(callEvent);
+        }
 
         return { status: 'received' };
     }