修复用户实测反馈的4处问题：品牌名泄露、修改密码页注释泄露、安全提醒页未居中、群相关行间距

- 品牌名：BASE_APP_NAME 从 "TinodeWeb" 改为 "MeetingIM"（关于页/青少年模式文案不再暴露 Tinode 字样）；
  logo-view.jsx（未选中会话时的空状态）去掉开源模板遗留的 Tinode 主页/GitHub 链接/原始版本号，
  换成品牌图标+"选择一个会话开始聊天"
- personal-settings-view.jsx：删除 ChangePassword 页面里被误当正文渲染的开发注释（提及 Tinode 协议），
  改回真正的代码注释
- base.css：.risk-info-page（安全提醒整页）补 margin:0 auto——原来复用模态弹窗的 .risk-dialog 样式，
  宽屏下整块内容贴左显示，没有居中
- base.css：.group-member-picker/.group-settings-header/.group-member-section-title 的 strong/small
  漏加入既有的 line-height:1.3 覆盖名单，继承通用 button{line-height:2.2rem}，导致群成员列表/群聊设置
  头部的姓名与角色/简介文字行间距异常大、贴底部分割线过近

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/config.js

@@ -1,7 +1,8 @@
 import { PACKAGE_VERSION } from './version.js';
 
-// Version-independent name of this application, used for Firebase app name.
-export const BASE_APP_NAME = 'TinodeWeb';
+// Version-independent name of this application, used for Firebase app name and shown to users
+// (about page, youth-mode copy).
+export const BASE_APP_NAME = 'MeetingIM';
 // Name of this application, used in the User-Agent.
 export const APP_NAME = BASE_APP_NAME + '/' + (PACKAGE_VERSION || '0.25');
 

src/views/logo-view.jsx

@@ -1,25 +1,18 @@
-/* This is just a static page to display when no conversation is selected. */
+/* Static placeholder shown in the message pane when no conversation is selected. */
 import React from 'react';
-import { FormattedMessage } from 'react-intl';
 
-import { Tinode } from 'tinode-sdk';
+import { BASE_APP_NAME } from '../config.js';
 
-import { APP_NAME } from '../config.js';
+function Icon({children}) { return <i className="material-icons" aria-hidden="true">{children}</i>; }
 
 export default class LogoView extends React.PureComponent {
   render() {
-    const version = APP_NAME + ' (' + Tinode.getLibrary() + ')';
     return (
       <div id="dummy-view">
         <div>
-          <a href="https://github.com/tinode/chat/">
-            <img id="logo" alt="logo" src="img/logo.svg" />
-            <h2>Tinode Web</h2>
-          </a>
-          <p><FormattedMessage id="label_client" defaultMessage="Client:"
-            description="Label for a client version" /> {version}</p>
-          <p><FormattedMessage id="label_server" defaultMessage="Server:"
-            description="Label for a server version" /> {this.props.serverVersion} ({this.props.serverAddress})</p>
+          <span id="dummy-view-icon"><Icon>forum</Icon></span>
+          <h2>{BASE_APP_NAME}</h2>
+          <p>选择一个会话开始聊天</p>
         </div>
       </div>
     );

src/views/messages-view.jsx

@@ -2127,9 +2127,7 @@ class MessagesView extends React.Component {
 
     let component;
     if (!this.state.topic) {
-      component = <LogoView
-          serverVersion={this.props.serverVersion}
-          serverAddress={this.props.serverAddress} />;
+      component = <LogoView />;
 
     } else {
       let component2;

src/views/personal-settings-view.jsx

@@ -395,6 +395,8 @@ function ClearHistoryConfirm({tinode, chatList, onToast}) {
 // (Tinode.updateAccountBasic), already wired end-to-end via tinode-web.jsx's
 // handleUpdatePasswordRequest/onUpdatePassword prop (used today by the old acc-security-view.jsx).
 // Reusing that verified callback here instead of reimplementing the WS call.
+// The server-side account-update call never checks the caller's current password -- "原密码" below
+// is a frontend-only speed bump against fat-fingering this field, not a real credential check.
 function ChangePassword({onUpdatePassword, onToast}) {
   const [oldPwd, setOldPwd] = React.useState('');
   const [newPwd, setNewPwd] = React.useState('');
@@ -421,7 +423,6 @@ function ChangePassword({onUpdatePassword, onToast}) {
     <label><span>原密码</span><input type="password" value={oldPwd} onChange={e => setOldPwd(e.target.value)} placeholder="请输入当前密码" /></label>
     <label><span>新密码</span><input type="password" value={newPwd} onChange={e => setNewPwd(e.target.value)} placeholder="至少6位" /></label>
     <label><span>确认新密码</span><input type="password" value={confirmPwd} onChange={e => setConfirmPwd(e.target.value)} placeholder="再次输入新密码" /></label>
-    <p>Tinode 协议本身不会在服务端校验"原密码"，这里的原密码输入是前端自己加的一道二次确认，防止误触。</p>
   </main></div>;
 }