server {
  listen 80;
  root /usr/share/nginx/html;
  index index.html;
  location / { try_files $uri $uri/ /index.html; }
  location /api/ { proxy_pass http://backend:3001; }
  location /ws { proxy_pass http://backend:3001; proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection "upgrade"; }
}