test: give federation integration suites a realistic per-test timeout (#7)

The three test/ files boot real federated instances and drive S2S over HTTP,
with several tests deliberately waiting on log matchers (e.g. logMatched(...,
1_000) per remote). Vitest's 5s default per-test timeout is meant for unit tests
and is too tight here: under CI load the multi-remote fan-out tests in
federation-identity-deletion intermittently timed out (observed on the post-merge
main run), producing a flaky red check.

Set a file-level testTimeout of 30s in each of the three harness-based suites via
vi.setConfig. Scoped per-file so unit tests keep the strict 5s default; a genuine
hang still trips the 30s ceiling well before the 90s hook budget. No test logic
changed.

packages/server/test/federation-handshake-desync.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect, afterEach } from 'vitest';
+import { describe, it, expect, afterEach, vi } from 'vitest';
 import {
   bootTwoInstancesForHandshake,
   registerAdmin,
@@ -11,6 +11,12 @@ import {
 import type { TwoInstanceHarness } from './helpers/twoInstanceHarness.js';
 import { openInspector } from './helpers/dbInspect.js';
 
+// Boots real federated instances and drives the peering handshake over HTTP; the
+// 5s unit-test default is too tight under CI load. See
+// federation-identity-deletion.test.ts for the rationale. A genuine hang still
+// trips this ceiling.
+vi.setConfig({ testTimeout: 30_000 });
+
 /**
  * Acceptance-gate integration suite for the federation handshake desync bugs.
  *