test(ws): bound the load test's unregister settle by overallTimeout, not 5s (#1379)

TestTheLoadTest failed on the post-merge main run's windows-latest -race leg
(job 95067154071) with "timed out after 5s waiting for churned clients to
fully unregister" — every worker had finished, the hub was still running,
and the goleak dump that followed was only the anchor drainers the t.Fatal
skipped stopping. The runner was simply slow: the ws package took 276s
against 159s on the identical tree an hour earlier, db and service ran
13-24% slower too, and Unregister drains asynchronously behind the hub
loop's remaining broadcast work.

Bound the settle wait by the test's own overallTimeout (90s), the same
"only a genuine hang takes this long" limit the workers use. waitFor
returns as soon as ClientCount matches, so a healthy run pays nothing —
locally under -race the whole test still finishes in ~9s.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Server/ws/load_soak_test.go

@@ -261,8 +261,15 @@ func TestTheLoadTest(t *testing.T) {
 	}
 
 	// Only the anchors should remain registered — every churned client
-	// unregistered itself at the end of its own round.
-	waitFor(t, 5*time.Second, func() bool { return hub.ClientCount() == numAnchors },
+	// unregistered itself at the end of its own round. Those Unregister calls
+	// are async: they queue behind whatever broadcast work the hub loop still
+	// holds, and how long that drain takes scales with the runner. A fixed 5s
+	// budget failed on a slow windows-latest -race runner (the whole package
+	// ran 74% slower than usual) while the workers themselves had finished
+	// fine — so bound the settle by the same "only a genuine hang takes this
+	// long" limit the workers use. waitFor returns the moment the count
+	// matches, so a healthy run pays nothing extra.
+	waitFor(t, overallTimeout, func() bool { return hub.ClientCount() == numAnchors },
 		"churned clients to fully unregister")
 	if got := hub.ClientCount(); got != numAnchors {
 		t.Errorf("ClientCount = %d after churn settled, want %d (anchors only)", got, numAnchors)