Refactor settings form and layout; enhance form submission with JSON handling and improve modal functionality for room management

templates/layout.html

@@ -53,10 +53,7 @@
         </div>
     </nav>
     <main class="container-flex m-5">
-        <form method="POST" id="settingsForm" action="{{ url_for('main.' + endpoint, **(endpoint_args or {})) }}">
             {% block content %}{% endblock %}
-            <input type="hidden" name="formState" id="formStateField">
-        </form>
     </main>
 
     <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.6/dist/js/bootstrap.bundle.min.js"