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>

routers/api/v1/admin/action.go

@@ -99,5 +99,5 @@ func ListWorkflowRuns(ctx *context.APIContext) {
 	//   "404":
 	//     "$ref": "#/responses/notFound"
 
-	shared.ListRuns(ctx, 0, 0)
+	shared.ListRuns(ctx, 0, 0, "")
 }