TLS support

The experimental flag that allows to override the go-sync server from the UI was merged to Nightly, but with the caveat of enforcing HTTPS usage for most deployment scenarios: https://github.com/brave/brave-core/pull/28463

I assume you use some reverse-proxy in production with go-sync, so it would be useful to at least mention that in the README that TLS is basically required or, ideally, add optional caddy/nginx setup to `docker-compose.yaml` for home-brew TLS with Lets Encrypt.

Start with the README and docker-compose.yaml, then review the linked brave-core pull request for the HTTPS requirement. Determine whether the contribution will document the TLS requirement or add an optional Caddy/nginx setup, and consider the work done when the chosen deployment guidance is present and accurate.

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