Add Docker development environment

Multistage Dockerfile (WooCommerce download, wp-bootstrap npm build,
Composer deps, WordPress runtime), Compose stack with MariaDB, and
auto-setup entrypoint that installs WordPress and activates the theme
on first boot.

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

compose.yaml

@@ -0,0 +1,45 @@
+services:
+  db:
+    image: mariadb:11
+    volumes:
+      - db_data:/var/lib/mysql
+    environment:
+      MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD:-rootpass}
+      MYSQL_DATABASE: ${MYSQL_DATABASE:-wordpress}
+      MYSQL_USER: ${MYSQL_USER:-wordpress}
+      MYSQL_PASSWORD: ${MYSQL_PASSWORD:-wordpress}
+    healthcheck:
+      test: ["CMD", "healthcheck.sh", "--connect", "--innodb_initialized"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  wordpress:
+    build:
+      context: .
+      dockerfile: docker/Dockerfile
+      additional_contexts:
+        wp-bootstrap: ../wp-bootstrap
+      target: wp_runtime
+    ports:
+      - "${WP_PORT:-8080}:80"
+    environment:
+      WORDPRESS_DB_HOST: db
+      WORDPRESS_DB_NAME: ${MYSQL_DATABASE:-wordpress}
+      WORDPRESS_DB_USER: ${MYSQL_USER:-wordpress}
+      WORDPRESS_DB_PASSWORD: ${MYSQL_PASSWORD:-wordpress}
+      WP_AUTO_SETUP: ${WP_AUTO_SETUP:-1}
+      WP_URL: ${WP_URL:-http://localhost:${WP_PORT:-8080}}
+      WP_TITLE: ${WP_TITLE:-WC Bootstrap Dev}
+      WP_ADMIN_USER: ${WP_ADMIN_USER:-admin}
+      WP_ADMIN_PASSWORD: ${WP_ADMIN_PASSWORD:-admin}
+      WP_ADMIN_EMAIL: ${WP_ADMIN_EMAIL:-admin@example.com}
+    depends_on:
+      db:
+        condition: service_healthy
+    volumes:
+      - wp_data:/var/www/html
+
+volumes:
+  db_data:
+  wp_data: