feat: Prepare Zemailnator for Dokploy deployment

- Add highly optimized Dockerfile with Nginx and PHP-FPM 8.4
- Add docker-compose.yml configured with Redis and MariaDB 10.11
- Implement entrypoint.sh and supervisord.conf for background workers
- Refactor legacy IMAP scripts into scheduled Artisan Commands
- Secure app by removing old routes with hardcoded basic auth credentials
- Configure email attachments to use Laravel Storage instead of insecure public/tmp

.docker/entrypoint.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+set -e
+
+echo "Storage symlink..."
+php artisan storage:link || true
+
+echo "Optimize cache..."
+php artisan optimize:clear
+php artisan config:cache
+php artisan route:cache
+php artisan view:cache
+
+echo "Running migrations..."
+php artisan migrate --force || true
+
+# Pass hand off to supervisor
+exec /usr/bin/supervisord -c /etc/supervisor/conf.d/supervisord.conf