feat: KPI细条新增两项完成率 + 侧边菜单加两个占位项

frontend/src/components/Layout/SideNav.css

@@ -35,4 +35,28 @@
 .side-nav-menu .ant-menu-item-selected {
   background: var(--color-accent-green) !important;
   color: var(--color-primary-green) !important;
-}
+}
+
+/* disabled 项整体灰化 + 不可点击 */
+.side-nav-menu .ant-menu-item-disabled {
+  opacity: 0.55;
+  cursor: not-allowed !important;
+}
+
+/* 即将上线小标签 */
+.menu-soon-tag {
+  font-size: 10px;
+  color: #999;
+  background: #f0f0f0;
+  padding: 1px 5px;
+  border-radius: 4px;
+  margin-left: 6px;
+  vertical-align: middle;
+  white-space: nowrap;
+}
+
+/* disabled 项内标签不受 opacity 影响 */
+.side-nav-menu .ant-menu-item-disabled .menu-soon-tag {
+  opacity: 1;
+  color: #888;
+}

frontend/src/components/Layout/SideNav.jsx

@@ -7,6 +7,7 @@ import {
   SyncOutlined,
   UserOutlined,
   TeamOutlined,
+  SoundOutlined,
 } from '@ant-design/icons'
 import useAuthStore from '../../stores/authStore'
 
@@ -23,6 +24,28 @@ function SideNav() {
     { key: '/doco', icon: <SyncOutlined />, label: '文稿对齐' },
     { key: '/editor-home', icon: <UserOutlined />, label: '个人首页' },
     { key: '/users', icon: <TeamOutlined />, label: '用户管理' },
+    {
+      key: 'tts-placeholder',
+      icon: <SoundOutlined />,
+      label: (
+        <span className="menu-item-with-tag">
+          蓝皓配音 TTS 2.0
+          <span className="menu-soon-tag">即将上线</span>
+        </span>
+      ),
+      disabled: true,
+    },
+    {
+      key: 'collab-placeholder',
+      icon: <TeamOutlined />,
+      label: (
+        <span className="menu-item-with-tag">
+          内部协作（Mattermost）
+          <span className="menu-soon-tag">即将上线</span>
+        </span>
+      ),
+      disabled: true,
+    },
   ]
 
   // 按角色过滤菜单项