test(benchmark): report each scenario as it finishes

Print the report header before the measured runs and each scenario's rows
as soon as its repetitions complete, so a timed-out job still shows the
finished scenarios. The final report, scenarios, warm-ups, repetitions,
assertions, heap limit and timeout are unchanged.

Refs #281

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app/benchmark/leave-planner-benchmark.spec.ts

@@ -1,7 +1,9 @@
 import { vi } from 'vitest';
 import { createPlanningCalculation } from '../services/leave-planner.service';
 import {
+	BENCHMARK_REPORT_HEADER,
 	benchmarkReport,
+	benchmarkReportRows,
 	benchmarkScenarios,
 	runLeavePlannerBenchmark,
 } from './leave-planner-benchmark';
@@ -64,7 +66,10 @@ describe('leave planner benchmark protocol', () => {
 					),
 				).toHaveLength(2);
 			}
-			const measurements = await runLeavePlannerBenchmark(2);
+			console.info(BENCHMARK_REPORT_HEADER);
+			const measurements = await runLeavePlannerBenchmark(2, (rows) =>
+				console.info(benchmarkReportRows(rows)),
+			);
 			for (const [name, placements] of [
 				['two years', 60],
 				['three years', 90],