Filing an issue as unkin-agent means hand-rolling a POST to the issues
API with a manually minted token, the exact credential handling agentpr
exists to encapsulate.
- add `issue create`, `issue comment` and `issue edit`, mirroring the pr
command group's flags, output and errors
- add CreateIssue/EditIssue to the Gitea client, sharing EditOptions with
EditPR
- build both comment commands from one constructor so pr and issue
comments cannot drift off Gitea's shared endpoint
- cover create, edit, a missing repo, an API error and missing flags
unkin-agent
3de9d35699