Fix self-hosted authentication issues

[RijulTP]

Summary

Fixes an issue where git-lrc failed to authenticate when connecting to self-hosted servers. The self-hosted authentication flow has been updated to ensure successful login and setup.

Checklist

• This PR fulfills an agreed issue.
• I kept the change narrow and scoped.
• I ran the most specific relevant validation and described it above.
• If I changed behavior, I called that out clearly in this PR.
• If I changed network/ responsibilities, I updated network/network_status.md and ran make check-status-doc.
• If this change touches security, disclosure flow, credentials, storage, network behavior, or remote data handling, I reviewed SECURITY.md and updated related documentation if needed.