Audit fixes.

peer/on_hub_test.go

@@ -268,7 +268,7 @@ func TestSwitchActiveRelay(t *testing.T) {
 			name: "stale relay demoted to direct before backup elected",
 			setup: func(t *testing.T, a *App) {
 				old := addRelayPeer(t, a, "10.0.0.10", ep1)
-				old.wgPeer.LastHandshakeTime = time.Time{} // stale — triggers switch from onTick
+				old.LastPing = time.Time{} // stale — Up() checks LastPing; triggers switch — triggers switch from onTick
 				a.relay = old
 				addRelayPeer(t, a, "10.0.0.11", ep2)
 			},