refactor: rename gitlab_domain_name annotation to git_domain_name for non-workshop genericity

[allamand]

Context

The cluster secret annotation gitlab_domain_name is used by ArgoCD ApplicationSet templates (in gitops/addons/registry/) to configure the Git server integration domain for Backstage, ArgoCD repo credentials, and other addons.

In the workshop setup, this is the EC2 GitLab CloudFront domain. In non-workshop deployments, it could be any Git server (GitHub, Bitbucket, Gitea, etc.).

Problem

The name gitlab_domain_name is GitLab-specific and implies a tight coupling to GitLab. Non-workshop users may not use GitLab at all.

Proposed Change

Rename gitlab_domain_name → git_domain_name (or git_server_domain) across:

• gitops/addons/registry/*.yaml — ApplicationSet templates
• cluster-providers/kind-crossplane/Taskfile.yaml — hub:seed METADATA
• cluster-providers/kind-kro-ack/Taskfile.yaml — hub:seed metadata
• Any helm chart templates that reference .Values.global.gitlab_domain_name

Backward Compatibility

Add a fallback in templates: {{default .metadata.annotations.git_domain_name .metadata.annotations.gitlab_domain_name}} during transition.

Related

• Workshop-specific usage of this field is in cluster-providers/workshop/Taskfile.yaml (reads from private/gitlab-cloudfront-domain)
• This is a non-breaking rename if done with the fallback pattern