docker: NPM joins dmtools_default, not a shared proxy network

NPM (nginx_app_1) is connected to each stack's own default network by
hand, not to a shared docker_default. Drop the unused external `proxy`
network from the compose file; nginx just lives on dmtools_default.
setup.sh now connects NPM to it (no-op if already connected) and prints
the proxy-host settings.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docker/setup.sh

@@ -114,6 +114,15 @@ pexec php bin/console asset-map:compile
 # php-fpm runs as www-data and must be able to write there at runtime.
 pexec chown -R www-data:www-data var
 
+# Make sure Nginx Proxy Manager can reach this stack's nginx by name.
+# Harmless (and a no-op) if already connected; NPM keeps it across restarts.
+NPM_CONTAINER="${NPM_CONTAINER:-nginx_app_1}"
+if docker inspect "$NPM_CONTAINER" >/dev/null 2>&1; then
+  docker network connect "${PROJECT}_default" "$NPM_CONTAINER" 2>/dev/null \
+    && echo "Connected $NPM_CONTAINER to ${PROJECT}_default." \
+    || true
+fi
+
 APP_URL="http://localhost:${NGINX_PORT:-8085}"
 cat <<EOT
 
@@ -121,6 +130,10 @@ Setup complete!
 
 Open the app:  $APP_URL   (real access is via https://dmtools.fvandenberg.nl through NPM)
 
+NPM proxy host: scheme http, forward "dmtools-nginx" port 80.
+If NPM ($NPM_CONTAINER) can't reach it, run:
+  docker network connect ${PROJECT}_default $NPM_CONTAINER
+
 Create the first user:
   $DOCKER_COMPOSE -p $PROJECT exec php php bin/console app:user:create you@example.com --admin