build Stage Finished Console Log
fun buildStageFinishedConsoleLog(stageRecord: StageRecord, stagePath: List<String>, parentRecord: StageRecord?): String
Multi-line summary of a finished stage: substage counts, timing (elapsed, averages, ETC), dataset results when present, consumption, any failure, and an optional parent ETC hint. Reads aggregated values from StageRecord.metrics; parentRecord is null for top-level stages.