Set up custom domain + HTTPS

[krapfj23]

Summary

Configure a custom domain with HTTPS for the deployed API.

Blocked by

• Deploy to cloud + configure env vars #60 (deploy to cloud)

Blocks

Nothing

Steps

1. Register or choose a domain/subdomain for the API (e.g., api.cortex.example.com)
2. Configure DNS records (CNAME or A record) pointing to the cloud provider
3. Enable HTTPS/TLS in the cloud provider dashboard (most auto-provision via Let's Encrypt)
4. Update docs/deployment.md with domain configuration steps

Acceptance Criteria

• Custom domain resolves to the deployed app
• HTTPS works (no certificate warnings)
• docs/deployment.md updated with domain setup steps
• PR body includes Closes #61