Feature request: GitLab integration support

[p38wassim]

Feature Request: GitLab Support

Summary

Currently, Fusion only supports GitHub for issue tracking and repository integration. It would be great to also support GitLab as an alternative, since many teams and self-hosted setups use GitLab instead of (or alongside) GitHub.

Current Behavior

• The Settings → Project General section has a "GitHub Tracking" section with a owner/repo field hardcoded for GitHub.
• • The fn CLI has no auth gitlab command.
• • • The "GitHub not connected" banner and all related UI references are GitHub-specific.
• • • • There is no way to connect Fusion to a GitLab instance (cloud or self-hosted).

Desired Behavior

• Support GitLab as a provider for issue tracking (similar to the existing GitHub integration).
• • Allow configuring a GitLab PAT or OAuth token via CLI or Settings.
• • • Support both gitlab.com and self-hosted GitLab instances (configurable base URL).
• • • • Allow the "Project Default Tracking Repo" to point to a GitLab project (e.g. group/project).

Use Case

Users running Fusion locally or in self-hosted environments often use GitLab for version control and issue management. Adding GitLab support would significantly broaden Fusion's appeal and usability for those teams.

Additional Context

• Fusion version: v0.51.0
• • Deployment: local/self-hosted
• • • OS: Windows