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>

deploy/backup.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+# Off-host database + uploads backup (design doc §01, launch gate: "A full
+# backup has been restored successfully into staging" — see restore.sh).
+set -euo pipefail
+
+ENVIRONMENT="${1:?Usage: backup.sh <staging|production>}"
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$REPO_ROOT"
+
+ENV_FILE=".env.${ENVIRONMENT}"
+set -a
+# shellcheck disable=SC1090
+source "$ENV_FILE"
+set +a
+
+TIMESTAMP="$(date +%Y%m%d-%H%M%S)"
+BACKUP_DIR="${BACKUP_DIR:-./backups}/${ENVIRONMENT}"
+mkdir -p "$BACKUP_DIR"
+
+COMPOSE="docker compose -f docker-compose.yml -f docker-compose.${ENVIRONMENT}.yml --env-file ${ENV_FILE}"
+
+echo "==> dumping database"
+$COMPOSE exec -T db sh -c "exec mysqldump -u\"\$MARIADB_USER\" -p\"\$MARIADB_PASSWORD\" \"\$MARIADB_DATABASE\"" \
+  | gzip > "$BACKUP_DIR/db-${TIMESTAMP}.sql.gz"
+
+echo "==> archiving uploads"
+$COMPOSE run --rm -T wordpress tar -czf - -C /var/www/html/wp-content uploads \
+  > "$BACKUP_DIR/uploads-${TIMESTAMP}.tar.gz"
+
+if [[ -n "${BACKUP_REMOTE:-}" ]]; then
+  echo "==> syncing to off-host storage ($BACKUP_REMOTE)"
+  rclone copy "$BACKUP_DIR/db-${TIMESTAMP}.sql.gz" "$BACKUP_REMOTE/${ENVIRONMENT}/"
+  rclone copy "$BACKUP_DIR/uploads-${TIMESTAMP}.tar.gz" "$BACKUP_REMOTE/${ENVIRONMENT}/"
+else
+  echo "==> BACKUP_REMOTE not set — backup stayed local only; configure rclone before launch"
+fi
+
+echo "==> pruning local backups older than ${BACKUP_RETENTION_DAYS:-14} days"
+find "$BACKUP_DIR" -type f -mtime "+${BACKUP_RETENTION_DAYS:-14}" -delete
+
+echo "==> backup complete: $BACKUP_DIR"