fix(web): 修复场景名称和更新登录页面徽标

- 将 Playground 组件中的 scene_name 更改为 chat_scene
- 更新登录页面的徽标图片路径

web/pages/index.tsx

@@ -271,7 +271,7 @@ const Playground: NextPage = () => {
               )}
             </div>
           }
-          scene={item?.team_context?.scene_name || 'chat_agent'}
+          scene={item?.team_context?.chat_scene || 'chat_agent'}
         />
       </div>
     );

web/pages/login.tsx

@@ -49,7 +49,7 @@ const LoginPage: FC = () => {
       {/* 登录表单容器 */}
       <div className='relative z-10 flex h-full items-center justify-end pr-24'>
         <div className='w-96 rounded-lg bg-white bg-opacity-90 p-6 shadow-lg backdrop-blur-sm'>
-          <Image width={'100%'} preview={false} src='/LOGO_1.png' />
+          <Image width={'100%'} preview={false} src='/LOGO.png' />
           <Form onFinish={values => doLoginFn(values)}>
             {/* 保持原有表单项目不变 */}
             <Form.Item name='username' rules={[{ required: true, message: '请输入用户名' }]}>