feat: add Platform GraphQL client service for lead lookup and CRUD

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

src/app.module.ts

@@ -1,6 +1,7 @@
 import { Module } from '@nestjs/common';
 import { ConfigModule } from '@nestjs/config';
 import configuration from './config/configuration';
+import { PlatformModule } from './platform/platform.module';
 
 @Module({
     imports: [
@@ -8,6 +9,7 @@ import configuration from './config/configuration';
             load: [configuration],
             isGlobal: true,
         }),
+        PlatformModule,
     ],
 })
 export class AppModule {}