[client] Trigger login from the expired tray session row

The expired-session tray click navigated the main window to /#/login,
a route that does not exist and falls through to the main page without
starting a login. Emit the trigger-login event instead, matching
handleConnect's SessionExpired path.

client/ui/tray_session.go

@@ -308,11 +308,7 @@ func (t *Tray) openSessionExtendFlow() {
 	}
 	seconds := int(time.Until(deadline).Seconds())
 	if seconds <= 0 {
-		if t.window != nil {
-			t.window.SetURL("/#/login")
-			t.window.Show()
-			t.window.Focus()
-		}
+		t.app.Event.Emit(services.EventTriggerLogin)
 		return
 	}
 	if t.svc.WindowManager == nil {