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>

css/base.css

@@ -3955,12 +3955,29 @@ img.channel {
   align-items: center;
   justify-content: center;
   background-color: var(--clr-cyan-50);
-}
-#dummy-view a {
-  text-decoration: none;
-  display: block;
   text-align: center;
 }
+#dummy-view-icon {
+  display: grid;
+  place-items: center;
+  width: 6.5rem;
+  height: 6.5rem;
+  margin: 0 auto 0.8rem;
+  border-radius: 1.2rem;
+  color: #fff;
+  background: #2878d6;
+}
+#dummy-view-icon .material-icons {
+  font-size: 4.2rem;
+}
+#dummy-view h2 {
+  margin: 0;
+  font-size: 1.25rem;
+}
+#dummy-view p {
+  margin: 0.25rem 0 0;
+  color: #777f89;
+}
 
 #image-preview {
   position: absolute;
@@ -9164,7 +9181,8 @@ div.toast.show {
 .group-list strong,
 .group-request-list strong,
 .group-admin-page strong,
-.group-muted-list strong {
+.group-muted-list strong,
+.group-member-picker strong {
   line-height: 1.3;
 }
 
@@ -9176,7 +9194,8 @@ div.toast.show {
 .group-list small,
 .group-request-list small,
 .group-admin-page small,
-.group-muted-list small {
+.group-muted-list small,
+.group-member-picker small {
   margin-top: 0.2rem;
   color: #9299a2;
   font-size: 0.75rem;
@@ -9882,7 +9901,11 @@ div.toast.show {
    自己的 place-items:center 就只剩交叉轴（水平）生效，主轴（垂直）退回 flex-start，
    里面的图标会贴着方块顶部而不是居中。 */
 .group-settings-header > span:not(.group-avatar) { display: flex; flex-direction: column; gap: 0.15rem; min-width: 0; }
-.group-settings-header small { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; color: #9299a2; }
+/* Same generic `button { line-height: 2.2rem }` leak as .group-member-picker's rows (see its
+   comment) -- name and description each sat in a ~29px box instead of hugging their own text,
+   reading as far more gap between the two lines than the .15rem `gap` above actually specifies. */
+.group-settings-header strong { line-height: 1.3; }
+.group-settings-header small { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; color: #9299a2; line-height: 1.3; }
 
 .group-list > button {
   display: grid;
@@ -10223,11 +10246,13 @@ div.toast.show {
 .group-member-section-title > strong {
   color: #30353c;
   font-size: 1rem;
+  line-height: 1.3;
 }
 
 .group-member-section-title > small {
   margin-left: auto;
   color: #949ba4;
+  line-height: 1.3;
 }
 
 .group-settings section > .group-member-grid {
@@ -10540,11 +10565,6 @@ div.toast.show {
   flex-direction: column;
 }
 
-.group-member-picker small {
-  margin-top: 0.2rem;
-  color: #9299a2;
-}
-
 .group-check {
   display: grid;
   place-items: center;
@@ -13808,6 +13828,16 @@ div.toast.show {
   text-align: center;
 }
 
+/* .risk-dialog was designed as a modal card, centered by .risk-overlay's place-items:center wrapper
+   (RiskConfirmDialog). FraudAwareness reuses the same class directly as .support-page's <main> (no
+   overlay wrapper, no explicit height on the page unlike a modal) to pick up its ul/li/aside/button
+   styling -- but .support-page is a plain flex column with no centering of its own, so the capped
+   width left the whole page pinned to the left edge on anything wider than ~25rem instead of centered
+   like every other support-page/group-page/people-page in the app. */
+.risk-info-page {
+  margin: 0 auto;
+}
+
 .risk-symbol {
   display: grid;
   place-items: center;