test: add PI release proof harness

tests/unit/coding-chat-pressure.test.tsx

@@ -1,5 +1,5 @@
 import { act, render } from '@testing-library/react';
-import { mkdtemp, rm } from 'node:fs/promises';
+import { mkdtemp, rm, writeFile } from 'node:fs/promises';
 import { createServer } from 'node:http';
 import { tmpdir } from 'node:os';
 import path from 'node:path';
@@ -36,6 +36,16 @@ function percentile95(values: number[]): number {
   return ordered[Math.ceil(ordered.length * 0.95) - 1] ?? Number.POSITIVE_INFINITY;
 }
 
+function summarize(values: number[]): { samples: number; p50: number; p95: number; max: number } {
+  const ordered = [...values].sort((left, right) => left - right);
+  return {
+    samples: ordered.length,
+    p50: ordered[Math.ceil(ordered.length * 0.5) - 1] ?? Number.POSITIVE_INFINITY,
+    p95: percentile95(ordered),
+    max: ordered.at(-1) ?? Number.POSITIVE_INFINITY,
+  };
+}
+
 function pressurePatch(seq: number): ConversationPatch {
   if (seq === 1) {
     return {
@@ -203,7 +213,7 @@ describe('REN-008 coding timeline pressure', () => {
         latencies.push(performance.now() - startedAt);
       }
       const measuredReactCommits = reactCommits - initialCommits;
-      const p95Ms = percentile95(latencies);
+      const mainToReactMs = summarize(latencies);
       const metrics = {
         runtimePatchItems,
         patchBatches,
@@ -211,7 +221,8 @@ describe('REN-008 coding timeline pressure', () => {
         rendererTransactions,
         reactCommits: measuredReactCommits,
         wireBytes,
-        mainToReactP95Ms: p95Ms,
+        mainToReactMs,
+        mainToReactP95Ms: mainToReactMs.p95,
       };
       console.info('REN-008 metrics', metrics);
       expect(metrics.runtimePatchItems).toBe(100);
@@ -225,6 +236,8 @@ describe('REN-008 coding timeline pressure', () => {
         .entriesByConversationId[conversation.id]?.reducer.snapshot?.cursor.seq).toBe(100);
       view.unmount();
       unsubscribe();
+      const reportPath = process.env.MAKELORE_PI_PERF_PRESSURE_FRAGMENT;
+      if (reportPath) await writeFile(reportPath, `${JSON.stringify(metrics, null, 2)}\n`);
     } finally {
       controller.abort();
       await reader.cancel().catch(() => undefined);