fix: 도메인 배포 설정 (web-inspector.yakenator.io)

- NEXT_PUBLIC_API_URL을 same-origin(빈값)으로 변경 (Nginx 리버스 프록시 사용)
- Nginx 설정 추가 (SSE 버퍼링 OFF, API/Frontend 프록시)
- Dockerfile, docker-compose.yml 업데이트

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

docker-compose.yml

@@ -72,7 +72,7 @@ services:
     ports:
       - "${FRONTEND_PORT:-3011}:3000"
     environment:
-      - NEXT_PUBLIC_API_URL=http://backend:8000
+      - NEXT_PUBLIC_API_URL=
     depends_on:
       - backend
     networks: