Add Docker Compose production stack (php-apache, mariadb, node/pm2)

Single-command deploy: docker compose up -d --build brings up the LEMP
stack plus the Node realtime/scheduler service. app/config.php and DB
secrets are generated from .env at container start, never baked into
the image or committed.

docker/php/Dockerfile

@@ -0,0 +1,17 @@
+FROM php:8.3-apache
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        libzip-dev libicu-dev libonig-dev default-mysql-client gettext-base \
+    && docker-php-ext-install pdo_mysql mysqli mbstring gd zip intl sockets exif opcache \
+    && a2enmod rewrite \
+    && apt-get clean && rm -rf /var/lib/apt/lists/*
+
+COPY docker/php/opcache.ini /usr/local/etc/php/conf.d/opcache-recommended.ini
+COPY docker/php/entrypoint.sh /usr/local/bin/docker-entrypoint-wms.sh
+COPY docker/php/config.php.template /usr/local/etc/wms/config.php.template
+RUN chmod +x /usr/local/bin/docker-entrypoint-wms.sh
+
+WORKDIR /var/www/html/wms-app
+
+ENTRYPOINT ["docker-entrypoint-wms.sh"]
+CMD ["apache2-foreground"]