feat(api): Add GET /repos/{owner}/{repo}/actions/workflows/{workflow_id}/runs (#37196)

- Add GET /repos/{owner}/{repo}/actions/workflows/{workflow_id}/runs
endpoint, matching the
https://docs.github.com/en/rest/actions/workflow-runs?apiVersion=2026-03-10#list-workflow-runs-for-a-workflow

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: bircni <bircni@icloud.com>

modules/git/repo_commit_gogit.go

@@ -23,7 +23,10 @@ func (repo *Repository) GetRefCommitID(name string) (string, error) {
 	}
 	refName := plumbing.ReferenceName(name)
 	if err := refName.Validate(); err != nil {
-		return "", err
+		// Match the nogogit behavior: an unresolvable/invalid ref name
+		// is reported as not-existing rather than a generic validation error,
+		// so callers can rely on IsErrNotExist regardless of build tag.
+		return "", ErrNotExist{ID: name}
 	}
 	ref, err := repo.gogitRepo.Reference(refName, true)
 	if err != nil {