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

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

src/platform/platform.module.ts

@@ -0,0 +1,8 @@
+import { Module } from '@nestjs/common';
+import { PlatformGraphqlService } from './platform-graphql.service';
+
+@Module({
+    providers: [PlatformGraphqlService],
+    exports: [PlatformGraphqlService],
+})
+export class PlatformModule {}