feat: add production deployment config

- Add docker-compose.prod.yml and Caddyfile for Caddy reverse proxy
- Add production stages to frontend Dockerfile (nginx for static files)
- Fix monorepo package exports for production builds (dist/src paths)
- Add CORS_ORIGIN env var for cross-origin config
- Add Better Auth baseURL, cookie domain, and trusted origins from env
- Use VITE_API_URL for API calls in auth-client and play route
- Add credentials: include for cross-origin fetch requests
- Remove unused users table from schema

documentation/notes.md

@@ -7,6 +7,24 @@
 
 ## problems+thoughts
 
+### docker credential helper
+
+WARNING! Your credentials are stored unencrypted in '/home/languagedev/.docker/config.json'.
+Configure a credential helper to remove this warning. See
+https://docs.docker.com/go/credential-store/
+
+### vps setup
+
+monitoring and logging (eg via chrootkit or rkhunter, logwatch/monit => mails daily with summary)
+
+### cd/ci pipeline
+
+forgejo actions? smth else? where docker registry, also forgejo?
+
+### postgres backups
+
+how?
+
 ### try now option
 
 there should be an option to try the app without an account so users can see what they would get when creating an account