test(e2e): phase-3 add nightly full run and perf smoke checks (#717)

* test(e2e): phase-3 add nightly workflow and perf smoke suite

* test(e2e): address copilot review for phase-3 fixture and readiness flow

tests/e2e/specs/perf-smoke.spec.ts

@@ -0,0 +1,47 @@
+import { test, expect, request as playwrightRequest } from '@playwright/test';
+
+const fixtureBase = process.env.FIXTURE_BASE_URL || 'http://127.0.0.1:18080';
+const envMaxMs = Number(process.env.E2E_MAX_PREVIEW_MS);
+const maxMs = Number.isFinite(envMaxMs) ? envMaxMs : 15000;
+
+function b64(v: string): string {
+  return Buffer.from(v).toString('base64');
+}
+
+async function timedPreview(request: any, fileUrl: string) {
+  const started = Date.now();
+  const resp = await request.get(`/onlinePreview?url=${b64(fileUrl)}`);
+  const elapsed = Date.now() - started;
+  return { resp, elapsed };
+}
+
+test.beforeAll(async () => {
+  const api = await playwrightRequest.newContext();
+  const required = ['sample.txt', 'sample.docx', 'sample.xlsx'];
+  try {
+    for (const name of required) {
+      const resp = await api.get(`${fixtureBase}/${name}`);
+      expect(resp.ok(), `fixture missing or unavailable: ${name}`).toBeTruthy();
+    }
+  } finally {
+    await api.dispose();
+  }
+});
+
+test('perf: txt preview response under threshold', async ({ request }) => {
+  const { resp, elapsed } = await timedPreview(request, `${fixtureBase}/sample.txt`);
+  expect(resp.status()).toBe(200);
+  expect(elapsed).toBeLessThan(maxMs);
+});
+
+test('perf: docx preview response under threshold', async ({ request }) => {
+  const { resp, elapsed } = await timedPreview(request, `${fixtureBase}/sample.docx`);
+  expect(resp.status()).toBe(200);
+  expect(elapsed).toBeLessThan(maxMs);
+});
+
+test('perf: xlsx preview response under threshold', async ({ request }) => {
+  const { resp, elapsed } = await timedPreview(request, `${fixtureBase}/sample.xlsx`);
+  expect(resp.status()).toBe(200);
+  expect(elapsed).toBeLessThan(maxMs);
+});