[Bug] headscale uses cfg.BaseDomain for building FQDNs

[valkum]

Is this a support request?

• This is not a support request

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

The config currently knows of:

• cfg.BaseDomain: not configurable through the config.yaml, set to cfg.DNSConfig.BaseDomain, used for Domain in MapResponse
• cfg.DNSConfig.BaseDomain: described as the magic DNS base domain.

MapResponse.Domain is used by GUIs to show the tailnet organization name (text below your username).
Currently, you can only configure the magic DNS base domain which will be used as the organization name. This is also used to build the FQDNs in host mappings.

Expected Behavior

Be able to configure the organization name (organization domain) independently of the magic DNS base domain, as it is possible with tailscale.

Steps To Reproduce

1. run tailscale with webclient=true and observe that the magic DNS (called suffix in tailscale dns status) base domain is used as the org name at the top.

Environment

- OS: n/a
- Headscale version: 0.23
- Tailscale version: 1.78.1 macos/windows

Runtime environment

• Headscale is behind a (reverse) proxy
• Headscale runs in a container

Anything else?

I have a PR ready to fix this.