refactor: move Kong config to kong/ directory

Organize infrastructure configs properly:
- nginx/ for Nginx configuration
- kong/ for Kong configuration

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker-compose.yml

@@ -160,7 +160,7 @@ services:
       kong:
         condition: service_healthy
     volumes:
-      - ./scripts/init-kong.sh:/init-kong.sh:ro
+      - ./kong/init-kong.sh:/init-kong.sh:ro
     environment:
       KONG_ADMIN_URL: http://kong:8001
     command: ["/bin/sh", "/init-kong.sh"]