* fix(scripts): bind local make dev and make start to loopback
serve.sh and backend/Makefile started the Gateway with --host 0.0.0.0,
nginx.local.conf listened on every interface, and Next.js kept its
all-interfaces default outside Windows, so a local stack on a LAN or VPN
exposed ports 2026, 8001 and 3000, including /setup before the first
admin existed. The Docker stack and the README already document a
loopback-only default.
Bind the Gateway and frontend to 127.0.0.1 and keep nginx on loopback
unless BIND_HOST is set, the variable the Docker stack already honors.
nginx-local-conf.sh renders a copy listening on BIND_HOST, and serve.sh
resolves it before stopping anything so an invalid value cannot tear
down a running stack.
* docs(changelog): reference #6587
* docs(changelog): separate the loopback entry from the next bullet
---------
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>