feat: extract nginx from mp/nginx — initial libreshop/nginx

Source moved verbatim from mp/nginx/ on 2026-04-29; mp was the first
concrete adapter consuming the libreshop toolkit. Builds and publishes
git.librete.ch/libreshop/nginx on every main / v* push via the standard
.gitea/workflows/build.yml shared across libreshop components.

docker-entrypoint.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+set -e
+
+echo "Generated nginx.conf:"
+echo ""
+cat /etc/nginx/nginx.conf
+
+mkdir -p /cache/shop
+mkdir -p /cache/uploads
+mkdir -p /cache/api
+
+echo "Starting nginx"
+echo "NGINX_DEBUG=${NGINX_DEBUG}"
+# Start Nginx
+if [ "$NGINX_DEBUG" = "true" ]; then
+  sed -i 's/error\.log warn/error.log debug/' /etc/nginx/nginx.conf
+  exec nginx-debug -g 'daemon off;'
+else
+  exec nginx -g 'daemon off;'
+fi