web tests: raise the async query budget, ci contention timed out a suspended page

web/vitest.setup.ts

@@ -10,6 +10,8 @@
  * failing loudly.
  */
 
+import { configure } from "@testing-library/react";
+
 function escapeIdentifier(value: string): string {
 	let result = "";
 	for (let index = 0; index < value.length; index += 1) {
@@ -47,3 +49,14 @@ if (globalThis.CSS === undefined) {
 } else if (typeof globalThis.CSS.escape !== "function") {
 	globalThis.CSS.escape = escapeIdentifier;
 }
+
+/**
+ * Testing Library retries a `findBy*` query for 1000 ms by default. That is
+ * enough on an idle laptop — the whole suite resolves in well under a second —
+ * but not on a CI runner whose container competes for CPU with a concurrent
+ * zig build: `LocalDnsPage.test.tsx` timed out waiting for its heading while
+ * the page was still suspended on its first query (gates run 516, job 696).
+ * The budget is not the behaviour under test, so it is raised globally rather
+ * than per call; a test that genuinely never resolves still fails, only later.
+ */
+configure({ asyncUtilTimeout: 5000 });