feat(ui): add bootstrap toast for messages

app/templates/login.html

@@ -35,9 +35,6 @@
     <button type="submit" class="btn btn-primary">连接</button>
 </form>
 
-{% if message %}
-<div class="alert alert-{{ 'success' if success else 'danger' }} mt-4">{{ message }}</div>
-{% endif %}
 <script>
     document.addEventListener('DOMContentLoaded', () => {
         const tokenInput = document.getElementById('token');