chore: 불필요한 named volume 제거

- frontend_modules, backend_modules 볼륨 제거
- 컨테이너에서 npm install 시 호스트 node_modules에 직접 설치

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

docker-compose.yml

@@ -6,7 +6,6 @@ services:
       - "com.centurylinklabs.watchtower.enable=false"
     volumes:
       - ./frontend:/app
-      - frontend_modules:/app/node_modules
     depends_on:
       - fromis9-backend
     networks:
@@ -22,7 +21,6 @@ services:
       - .env
     volumes:
       - ./backend:/app
-      - backend_modules:/app/node_modules
     networks:
       - app
       - db
@@ -48,10 +46,6 @@ services:
       - app
     restart: unless-stopped
 
-volumes:
-  backend_modules:
-  frontend_modules:
-
 networks:
   app:
     external: true