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.override.yaml

@@ -0,0 +1,15 @@
+services:
+  db:
+    container_name: woocommerce-db
+
+  wordpress:
+    container_name: woocommerce
+    volumes:
+      - ../wp-bootstrap:/var/www/html/wp-content/themes/wp-bootstrap
+      - .:/var/www/html/wp-content/themes/wc-bootstrap
+    environment:
+      WORDPRESS_DEBUG: "1"
+      WORDPRESS_CONFIG_EXTRA: |
+        define('WP_DEBUG_LOG', true);
+        define('WP_DEBUG_DISPLAY', true);
+        define('SCRIPT_DEBUG', true);