test(e2e): a localhost connect the machine dropped is tried again on the test side

On a Windows host a burst of test traffic can drop a loopback connect now and then (every port,
any program — measured on the dev desktop). The browser resends it and only waits; Node (libuv)
sends a loopback SYN once and fails at ~300 ms with "connect ETIMEDOUT". `e2e/retryConnect.ts` wraps
Playwright's request context so that one error is tried again (0.5 / 1 / 2 / 4 / 8 s, the system's
own retry waits) while every other failure goes straight to the test; global.setup's health check,
login and /api/me and speed.measure's share probe go through it. Unit-tested; e2e 61/61.

frontend/e2e/speed.measure.ts

@@ -1,6 +1,7 @@
 import { test, type Page } from "@playwright/test";
 import { execFileSync } from "node:child_process";
 import { mkdirSync, writeFileSync } from "node:fs";
+import { retryConnect } from "./retryConnect";
 
 /**
  * The speed baseline: numbers, not assertions — read by `scripts/audit_metrics.py --speed`, which
@@ -83,7 +84,7 @@ test("speed baseline", async ({ browser, page: page0 }) => {
   // the visitor's tap — the page has no autoplay).
   let token: string | null = null;
   for (const t of shareTokens()) {
-    if ((await page0.request.get(`/api/public/watch/${t}`)).ok()) {
+    if ((await retryConnect(page0.request).get(`/api/public/watch/${t}`)).ok()) {
       token = t;
       break;
     }