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/nginx.conf

@@ -0,0 +1,32 @@
+server {
+    listen 80;
+    server_name _;
+    root /var/www/public;
+
+    add_header X-Frame-Options "SAMEORIGIN";
+    add_header X-Content-Type-Options "nosniff";
+
+    index index.php;
+
+    charset utf-8;
+
+    location / {
+        try_files $uri $uri/ /index.php?$query_string;
+    }
+
+    location = /favicon.ico { access_log off; log_not_found off; }
+    location = /robots.txt  { access_log off; log_not_found off; }
+
+    error_page 404 /index.php;
+
+    location ~ \.php$ {
+        fastcgi_pass 127.0.0.1:9000;
+        fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name;
+        include fastcgi_params;
+        fastcgi_hide_header X-Powered-By;
+    }
+
+    location ~ /\.(?!well-known).* {
+        deny all;
+    }
+}