run
open suspend override fun <T> runStage(name: String, substagesTotal: Int?, metrics: MetricsMap, block: suspend StageScope<Input, Output, InputLabel>.() -> T): Result<T>
Runs block as a named child stage and records the result.
On success: returns Result.success(block's value). On a regular exception: records the failure on the substage and returns Result.failure(StageFailedException) so callers can choose to handle or rethrow. On an ExecutionAbortException: records the failure on the substage and rethrows, letting the execution-level abort propagate up to the session.