[Bug] Inconsistency ‘givenName’ in node

[hopleus]

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

Host name where the error occurs - MacBook-Pro
(This is the real hostname of my machine)

When registering a node on the network, hostname as well as givenName is stored in its original form from tailcfg.Hostname - MacBook-Pro, without making it based on FQDN rules.
When renaming a node (changing the givenName), the logic checks the new name for FQDN compliance (CheckForFQDNRules) and does not allow the MacBook-Pro name to be saved, requiring lowercase i.e. macbook-pro.

Expected Behavior

When a node is registered on the network, the givenName is stored subject to FQDN rules.

Steps To Reproduce

1. Register node
2. Show givenName in DB
3. Try changing the node name to the same
4. Receive an FQDN error
5. Save the new node name taking into account the FQDN rules
6. It's OK, the new name is saved

Environment

- OS: MacOS 15
- Headscale version: 0.22.3
- Tailscale version: 1.74.0

Runtime environment

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

Anything else?

No response