fix(ai): clean up conversation timers on module destroy

Prevent leaked TTL timers from keeping Jest alive and add test cleanup.

Author: Emmanuel-Ugochukwu1

apps/api/src/modules/ai/ai.service.spec.ts

@@ -87,6 +87,11 @@ describe('AiService', () => {
     message: 'Tell me about the reentrancy finding',
   };
 
+  afterEach(() => {
+    // Clear any lingering conversation timers so Jest can exit cleanly.
+    service.clearConversation('user-1', 'audit-1');
+  });
+
   it('should be defined', () => {
     expect(service).toBeDefined();
   });

apps/api/src/modules/ai/ai.service.ts

@@ -3,6 +3,7 @@ import {
   Injectable,
   InternalServerErrorException,
   NotFoundException,
+  type OnModuleDestroy,
 } from '@nestjs/common';
 import { AiService as AiEngineService } from '@veridion/ai-engine';
 import { logger } from '@veridion/logger';
@@ -46,7 +47,7 @@ const MAX_HISTORY_LENGTH = 50;
 const CONVERSATION_TTL_MS = 30 * 60 * 1000; // 30 minutes
 
 @Injectable()
-export class AiService {
+export class AiService implements OnModuleDestroy {
   private readonly conversations = new Map<string, AiChatMessage[]>();
   private readonly conversationTimers = new Map<string, NodeJS.Timeout>();
 
@@ -148,6 +149,14 @@ export class AiService {
     }
   }
 
+  onModuleDestroy(): void {
+    for (const timer of this.conversationTimers.values()) {
+      clearTimeout(timer);
+    }
+    this.conversations.clear();
+    this.conversationTimers.clear();
+  }
+
   // ---- Private helpers ----
 
   private getOrCreateHistory(key: string): AiChatMessage[] {