discussion create: add label support via two-step GraphQL
- Add Labels []string field to CreateDiscussionInput
- Implement resolveLabels helper: paginated RepositoryLabels query,
case-insensitive match, error if any label not found
- Implement addLabelsToDiscussion helper: calls addLabelsToLabelable
mutation after createDiscussion
- Wire label logic into Create: resolve labels, apply them, populate
d.Labels from resolved values
- Add three TestCreate cases: success with labels, label not found,
mutation failure
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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