perf: enforce journey budgets and reference traces

scripts/aggregate-drive-traces.mjs

@@ -0,0 +1,11 @@
+#!/usr/bin/env node
+import { readFile } from 'node:fs/promises';
+import { aggregateFiveDriveTraces } from './lib/performance-aggregation.mjs';
+
+const paths = process.argv.slice(2);
+if (paths.length !== 5) throw new Error('Pass exactly five explicit drive-trace.v1 JSON paths.');
+const runs = [];
+for (const path of paths) runs.push(JSON.parse(await readFile(path, 'utf8')));
+const aggregate = aggregateFiveDriveTraces(runs);
+process.stdout.write(`${JSON.stringify(aggregate, null, 2)}\n`);
+if (!aggregate.passes) process.exitCode = 1;