feat: add AI enrichment service with Claude Haiku and rule-based fallback

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

src/ai/ai.module.ts

@@ -0,0 +1,8 @@
+import { Module } from '@nestjs/common';
+import { AiEnrichmentService } from './ai-enrichment.service';
+
+@Module({
+    providers: [AiEnrichmentService],
+    exports: [AiEnrichmentService],
+})
+export class AiModule {}

src/app.module.ts

@@ -1,6 +1,7 @@
 import { Module } from '@nestjs/common';
 import { ConfigModule } from '@nestjs/config';
 import configuration from './config/configuration';
+import { AiModule } from './ai/ai.module';
 import { PlatformModule } from './platform/platform.module';
 import { ExotelModule } from './exotel/exotel.module';
 
@@ -10,6 +11,7 @@ import { ExotelModule } from './exotel/exotel.module';
             load: [configuration],
             isGlobal: true,
         }),
+        AiModule,
         PlatformModule,
         ExotelModule,
     ],