ci: update compose.yml for prod deployment

- Add Nginx as a reverse proxy
- Add cert-selfsign.sh for generating self-signed certificates
- Add certbot-issue.sh for Let's Encrypt certificate issuance and renewal
- Add cron-install.sh and cron-uninstall.sh for system cron management
- Add .env.example as an environment variable template

.gitignore

@@ -104,4 +104,13 @@ screenshots/
 
 # Virutal Environments
 .venv/
-/.env
+
+# Environment variable files (keep .env.example)
+.env
+.env.*
+!.env.example
+
+nginx/certs/
+nginx/certbot/
+*.pem
+*.key