Week 1 infrastructure: Docker environments, deploy pipeline, bookstore-core scaffold

Docker Compose environments for dev/staging/production (MariaDB, Redis,
Caddy, Action Scheduler cron sidecar), an idempotent deploy script,
git-hook-based deploy pipeline, backup/restore scripts, and the
bookstore-core plugin stub with WooCommerce HPOS compatibility declared.

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

docker/php/php.ini

@@ -0,0 +1,13 @@
+[PHP]
+upload_max_filesize = 32M
+post_max_size = 32M
+memory_limit = 256M
+max_execution_time = 120
+max_input_vars = 3000
+
+[opcache]
+opcache.enable = 1
+opcache.memory_consumption = 128
+opcache.max_accelerated_files = 10000
+opcache.validate_timestamps = 1
+opcache.revalidate_freq = 2