feat: 配置功能仅admin可用，operator隐藏配置按钮+后端403拦截

- devices.html: 注入 USER_ROLE 全局变量
- devices.js: 配置按钮仅 USER_ROLE===admin 时渲染
- fixture.py: 页面/指令/保存三个路由均校验 admin 角色

edc-web/app/templates/devices.html

@@ -20,5 +20,8 @@
 {% endblock %}
 
 {% block scripts %}
+<script>
+    const USER_ROLE = "{{ current_user.role }}";
+</script>
 <script src="{{ url_for('static', filename='js/devices.js') }}"></script>
 {% endblock %}