Add nginx basic auth via docker-compose environment variables

Credentials set via AUTH_USER / AUTH_PASS in docker-compose.yml.
Entrypoint generates htpasswd at container start using openssl.

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

docker-entrypoint.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+set -e
+echo "${AUTH_USER}:$(openssl passwd -apr1 "${AUTH_PASS}")" > /etc/nginx/.htpasswd
+exec nginx -g "daemon off;"