Fix nginx routing: 127.0.0.1 instead of host.docker.internal

[gi-os]

Problem

nginx.js was generating shop location blocks using host.docker.internal as the upstream host. This hostname only resolves inside Docker containers — it is NOT resolvable by the host nginx process, causing nginx to fail its config test and refuse to reload, making new shops unreachable.

Also fixed: routing pattern now uses location /slug/ (trailing slash, no rewrite rules) matching the standard pattern used by demox, demoxi, edition, michael-kors. The old rewrite approach stripped the basePath prefix before passing to Next.js, breaking asset loading.

Fix

• proxy_pass http://127.0.0.1:${port} — resolves from host
• location /${slug}/ — trailing slash, no rewrite, passes full path to Next.js
• reloadNginx() now calls nginx -t && systemctl reload nginx directly instead of docker exec nginx-proxy

Affected shops

demo12 was the first shop created with the broken generator. Fixed manually on server.