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>

README.md

@@ -76,6 +76,13 @@ wc-bootstrap/
 │   ├── notices/
 │   ├── order/
 │   └── single-product/
+├── docker/
+│   ├── Dockerfile             # Multistage build (WC download, npm, composer, WP)
+│   ├── entrypoint.sh          # Auto-setup wrapper entrypoint
+│   ├── setup.sh               # First-run WP install + plugin/theme activation
+│   └── .env-dist              # Environment variable template
+├── compose.yaml               # WordPress + MariaDB services
+├── compose.override.yaml      # Dev overrides (bind mounts, debug flags)
 ├── composer.json
 ├── functions.php
 └── style.css
@@ -95,6 +102,29 @@ WooCommerce wc_get_template("cart/cart.php")
   → Result: Bootstrap 5 Twig output only
 ```
 
+### Docker Environment
+
+```bash
+# Copy and adjust environment variables (optional)
+cp docker/.env-dist .env
+
+# Build and start
+docker compose build
+docker compose up -d
+
+# WordPress installs automatically on first boot (admin/admin)
+# → http://localhost:8080
+# → http://localhost:8080/wp-admin/
+
+# Manual setup (if WP_AUTO_SETUP=0)
+docker compose exec wordpress setup.sh
+
+# Tear down
+docker compose down -v
+```
+
+The image preinstalls WooCommerce and wp-bootstrap. The override bind-mounts both themes for live development.
+
 ### Building Translations
 
 ```bash