feat: send RSVP confirmation emails using environment-based SMTP config; split EMAIL_FROM into EMAIL_FROM_NAME and EMAIL_FROM_ADDRESS

docker-compose.yml

@@ -9,6 +9,13 @@ services:
       - uploads:/app/uploads
     environment:
       - NODE_ENV=production
+      - EMAIL_HOST=smtp.example.com
+      - EMAIL_PORT=587
+      - EMAIL_USER=your@email.com
+      - EMAIL_PASS=yourpassword
+      - EMAIL_FROM_NAME=RSVP Manager
+      - EMAIL_FROM_ADDRESS=your@email.com
+      - EMAIL_SECURE=false
     restart: unless-stopped
 
 volumes: