feat(web): 用符合系统风格的组件替换全部 window.alert/confirm

全项目搜出15处 window.confirm、9处 window.alert（其中3处是各文件
各自复制的 notImplemented() 辅助函数，文案还都一样）用在退出登录、
删除消息/收藏/好友、清空聊天记录、解散群聊、转让群主、危险链接
二次确认等场景——全是浏览器原生弹窗，样式和整个应用的设计语言完全
脱节。

新增两个全局UI基础设施（Zustand store + 挂载在App.tsx根节点的
渲染组件，参照stores/calls.ts/messageJump.ts已有的"任何组件都能调用"
惯例，不是每个弹窗各自管理一份本地状态）：

- stores/confirmDialog.ts + app/ConfirmDialogRoot.tsx：替换
  window.confirm。requestConfirm()返回Promise<boolean>，和
  window.confirm的返回值语义一致，所以原来"if (!window.confirm(...))
  return"这一行改成"if (!(await requestConfirm({message:...})))
  return"，外层函数标成async，不用大改周围逻辑。危险/不可恢复操作
  （删除、解散群聊、注销账号等）传danger:true，确认按钮变红色，
  弹窗视觉沿用转发弹窗已有的"描边取消+实心确认"按钮搭配。
- stores/globalToast.ts + app/GlobalToastRoot.tsx：替换window.alert，
  复用应用里本来就有、每个页面各自本地状态管理的Toast组件。顺手把
  3个文件里各自重复定义、文案完全一样的notImplemented()合并成
  一个共享导出。

实机验证了非危险确认（清空缓存，蓝色确认按钮）、危险确认（删除
消息，红色确认按钮）、取消按钮、Escape键取消、全局提示（点"投诉
举报"）——均正常工作，且原有页面各自的Toast错误提示不受影响。

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

web/src/App.tsx

@@ -2,6 +2,8 @@ import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
 import { Navigate, createBrowserRouter, RouterProvider } from 'react-router-dom';
 
 import { AppShell } from '@/app/AppShell';
+import { ConfirmDialogRoot } from '@/app/ConfirmDialogRoot';
+import { GlobalToastRoot } from '@/app/GlobalToastRoot';
 import { RequireAuth } from '@/app/RequireAuth';
 import { EnterpriseRegisterPage } from '@/features/auth/EnterpriseRegisterPage';
 import { LoginPage } from '@/features/auth/LoginPage';
@@ -97,6 +99,11 @@ export default function App() {
   return (
     <QueryClientProvider client={queryClient}>
       <RouterProvider router={router} />
+      {/* Mounted above the router (not inside AppShell) -- window.confirm()/window.alert()
+          replacements need to work on unauthenticated pages too (e.g. TenantEntryPage's "switch
+          tenant" confirmation), not just the logged-in app tree. */}
+      <ConfirmDialogRoot />
+      <GlobalToastRoot />
     </QueryClientProvider>
   );
 }

web/src/app/ConfirmDialogRoot.tsx

@@ -0,0 +1,42 @@
+import { useEscapeKey } from '@/lib/hooks';
+import { useConfirmDialogStore } from '@/stores/confirmDialog';
+
+/** Mounted once at the app root (App.tsx) -- renders whatever `requestConfirm()` (confirmDialog.ts)
+ *  most recently asked for. Visual language matches this app's other small action dialogs (e.g. the
+ *  forward picker's outlined-gray "取消" + solid colored confirm button, `02-messages.dc.html`'s own
+ *  spec for that pairing) rather than inventing a new button treatment just for this. */
+export function ConfirmDialogRoot() {
+  const pending = useConfirmDialogStore((s) => s.pending);
+  const respond = useConfirmDialogStore((s) => s.respond);
+  // Always called (hooks can't be conditional) -- a no-op onEscape while nothing is pending is
+  // harmless, matching how every other modal in this app registers unconditionally too.
+  useEscapeKey(() => respond(false));
+
+  if (!pending) return null;
+  const { title, message, confirmLabel = '确定', cancelLabel = '取消', danger } = pending;
+
+  return (
+    <div className="fixed inset-0 z-[100] flex items-center justify-center bg-[#22262d]/25" onClick={() => respond(false)}>
+      <div className="w-[340px] rounded-xl bg-white p-5 shadow-modal" onClick={(e) => e.stopPropagation()}>
+        {title ? <strong className="mb-2 block text-base font-semibold text-text-heading">{title}</strong> : null}
+        <p className="m-0 text-sm leading-relaxed text-text-body">{message}</p>
+        <div className="mt-5 flex justify-end gap-3">
+          <button
+            type="button"
+            onClick={() => respond(false)}
+            className="grid h-9 place-items-center rounded-lg border border-[#d5d9df] px-4 text-sm text-text-secondary"
+          >
+            {cancelLabel}
+          </button>
+          <button
+            type="button"
+            onClick={() => respond(true)}
+            className={`grid h-9 place-items-center rounded-lg px-4 text-sm font-medium text-white ${danger ? 'bg-danger-text' : 'bg-btn'}`}
+          >
+            {confirmLabel}
+          </button>
+        </div>
+      </div>
+    </div>
+  );
+}

web/src/app/GlobalToastRoot.tsx

@@ -0,0 +1,14 @@
+import { Toast } from '@/app/Toast';
+import { useGlobalToastStore } from '@/stores/globalToast';
+
+/** Mounted once at the app root (App.tsx) -- renders whatever `notify()` (globalToast.ts) most
+ *  recently set. `key={token}` forces Toast to remount (not just re-render) so its own auto-dismiss
+ *  timer restarts even when the exact same message is fired twice in a row, which a plain `message`
+ *  string prop wouldn't detect as a change. */
+export function GlobalToastRoot() {
+  const message = useGlobalToastStore((s) => s.message);
+  const variant = useGlobalToastStore((s) => s.variant);
+  const token = useGlobalToastStore((s) => s.token);
+  if (!message) return null;
+  return <Toast key={token} message={message} variant={variant} onDone={() => useGlobalToastStore.setState({ message: '' })} />;
+}

web/src/features/auth/TenantEntryPage.tsx

@@ -7,6 +7,7 @@ import { Icon } from '@/app/Icon';
 import { ImApiError } from '@/lib/api/client';
 import { resolveTenant } from '@/lib/api/tenant';
 import { resetTinode } from '@/lib/tinode/connection';
+import { requestConfirm } from '@/stores/confirmDialog';
 import { parseWebsocketEndpoint, useSessionStore } from '@/stores/session';
 
 export function TenantEntryPage() {
@@ -25,7 +26,7 @@ export function TenantEntryPage() {
     // Reachable by navigating back here while already logged in (no route guard keeps an
     // authenticated user out of /tenant) -- resetTinode() below would otherwise silently tear down
     // that live session with no warning at all.
-    if (myUserId && !window.confirm('切换企业将退出当前登录，确定继续吗？')) return;
+    if (myUserId && !(await requestConfirm({ message: '切换企业将退出当前登录，确定继续吗？' }))) return;
     setSubmitting(true);
     setError('');
     try {

web/src/features/contacts/AddFriendModal.tsx

@@ -12,13 +12,10 @@ import { searchUsers, sendFriendRequest, type UserSearchResult } from '@/lib/api
 import { submitGroupJoinRequest } from '@/lib/api/groups';
 import type { QRResolveGroup, QRResolveUser } from '@/lib/api/qrcodes';
 import { useEscapeKey } from '@/lib/hooks';
+import { notImplemented } from '@/stores/globalToast';
 
 const MAX_MESSAGE_LENGTH = 50;
 
-function notImplemented() {
-  window.alert('该功能暂未开放，如需联系客服。');
-}
-
 interface AddFriendModalProps {
   onClose: () => void;
   onSent?: () => void;

web/src/features/favorites/FavoritesLayout.tsx

@@ -21,6 +21,7 @@ import { useAuthedBlobUrl, useDebouncedValue } from '@/lib/hooks';
 import { fileTypeStyle, formatFileSize } from '@/lib/messages/attachments';
 import { formatEventTimestamp } from '@/lib/messages/time';
 import { useChatList } from '@/lib/tinode/hooks';
+import { requestConfirm } from '@/stores/confirmDialog';
 
 const CATEGORIES: { key: FavoriteType | 'all'; label: string; icon: string }[] = [
   { key: 'all', label: '全部', icon: 'all_inbox' },
@@ -320,9 +321,9 @@ export function FavoritesLayout() {
     setSelectMode(false);
     setSelected(new Set());
   };
-  const bulkDelete = () => {
+  const bulkDelete = async () => {
     if (selected.size === 0) return;
-    if (!window.confirm(`删除已选择的 ${selected.size} 项收藏？`)) return;
+    if (!(await requestConfirm({ message: `删除已选择的 ${selected.size} 项收藏？`, danger: true }))) return;
     deleteMutation.mutate([...selected]);
   };
 

web/src/features/groups/GroupAdminModal.tsx

@@ -23,6 +23,7 @@ import {
 } from '@/lib/api/groups';
 import { avatarBgClass, avatarLetter } from '@/lib/avatar';
 import { useEscapeKey } from '@/lib/hooks';
+import { requestConfirm } from '@/stores/confirmDialog';
 import { useSessionStore } from '@/stores/session';
 
 interface GroupAdminModalProps {
@@ -478,8 +479,10 @@ function TransferOwnerSubView({ topicId, groupVersion, onClose }: { topicId: str
         topicId={topicId}
         cacheKey="eligible-owner"
         opts={{ eligibleRole: 'owner' }}
-        onPick={(m) => {
-          if (window.confirm(`确定将群主转让给 ${m.display_name || m.user_id} 吗？此操作不可撤销。`)) transferMutation.mutate(m.user_id);
+        onPick={async (m) => {
+          if (await requestConfirm({ message: `确定将群主转让给 ${m.display_name || m.user_id} 吗？此操作不可撤销。`, danger: true })) {
+            transferMutation.mutate(m.user_id);
+          }
         }}
         emptyLabel="没有可转让的成员"
         disabled={transferMutation.isPending}

web/src/features/groups/GroupDetailColumn.tsx

@@ -26,6 +26,8 @@ import {
 import type { MediaType } from '@/lib/api/messages';
 import { avatarBgClass, avatarLetter } from '@/lib/avatar';
 import { useTinode } from '@/lib/tinode/hooks';
+import { requestConfirm } from '@/stores/confirmDialog';
+import { notify } from '@/stores/globalToast';
 import { useSessionStore } from '@/stores/session';
 
 interface GroupDetailColumnProps {
@@ -155,21 +157,21 @@ export function GroupDetailColumn({ topicId, peerName, onClose, onOpenHistory }:
     onError: (err) => showError(err, '解散群聊失败'),
   });
 
-  const clearHistory = () => {
-    if (!window.confirm('确定清空本群的聊天记录吗？此操作仅清除本地记录，不影响其他成员。')) return;
+  const clearHistory = async () => {
+    if (!(await requestConfirm({ message: '确定清空本群的聊天记录吗？此操作仅清除本地记录，不影响其他成员。', danger: true }))) return;
     tinode.getTopic(topicId).delMessagesAll(false);
   };
 
   const reportAbuse = () => {
-    window.alert('该功能暂未开放，如需投诉举报请联系客服。');
+    notify('该功能暂未开放，如需投诉举报请联系客服。');
   };
 
-  const startLeaveOrDisband = () => {
+  const startLeaveOrDisband = async () => {
     if (isOwner) {
-      if (!window.confirm('解散群聊后，所有成员将无法再查看和发送消息，此操作不可恢复。确定解散吗？')) return;
+      if (!(await requestConfirm({ message: '解散群聊后，所有成员将无法再查看和发送消息，此操作不可恢复。确定解散吗？', danger: true }))) return;
       disbandMutation.mutate();
     } else {
-      if (!window.confirm('确定退出本群聊吗？')) return;
+      if (!(await requestConfirm({ message: '确定退出本群聊吗？', danger: true }))) return;
       leaveMutation.mutate();
     }
   };

web/src/features/groups/GroupFilesModal.tsx

@@ -9,6 +9,7 @@ import { fileAuthHeaders, fileDownloadUrl, uploadFile } from '@/lib/api/upload';
 import { useClickOutside, useDebouncedValue, useEscapeKey } from '@/lib/hooks';
 import { fileTypeStyle, formatFileSize } from '@/lib/messages/attachments';
 import { formatEventTimestamp } from '@/lib/messages/time';
+import { requestConfirm } from '@/stores/confirmDialog';
 import { useSessionStore } from '@/stores/session';
 
 function isPdf(f: GroupFile): boolean {
@@ -211,9 +212,11 @@ export function GroupFilesModal({ topicId, isAdmin, onClose }: GroupFilesModalPr
                         onClose={() => setOpenMenuId(null)}
                         onDownload={() => downloadFile(f)}
                         onOpen={() => openFileInNewTab(f)}
-                        onDelete={() => {
+                        onDelete={async () => {
                           setOpenMenuId(null);
-                          if (window.confirm(`确定删除文件"${f.file_name}"吗？`)) deleteMutation.mutate(f.group_file_id);
+                          if (await requestConfirm({ message: `确定删除文件"${f.file_name}"吗？`, danger: true })) {
+                            deleteMutation.mutate(f.group_file_id);
+                          }
                         }}
                         deleting={deleteMutation.isPending}
                       />

web/src/features/messages/ConversationView.tsx

@@ -30,6 +30,8 @@ import { useChatList, useTinode, useTopicMessages } from '@/lib/tinode/hooks';
 import { forwardMessage, sendPrebuiltContent, sendReply, sendText } from '@/lib/tinode/send';
 import { closeConversation, ensureTopicAttached, openConversation } from '@/lib/tinode/topics';
 import { useCallStore } from '@/stores/calls';
+import { requestConfirm } from '@/stores/confirmDialog';
+import { notImplemented } from '@/stores/globalToast';
 import { useMessageJumpStore } from '@/stores/messageJump';
 import { useSessionStore } from '@/stores/session';
 
@@ -50,10 +52,6 @@ interface ContextMenuState {
   msg: StoredMessage;
 }
 
-function notImplemented() {
-  window.alert('该功能暂未开放，如需联系客服。');
-}
-
 export function ConversationView() {
   const { topicId } = useParams();
   const { onToggleDetail, detailVisible, onOpenHistory } = useOutletContext<OutletCtx>();
@@ -443,9 +441,9 @@ export function ConversationView() {
     setSelectedSeqs(new Set());
   };
 
-  const bulkDelete = () => {
+  const bulkDelete = async () => {
     if (selectedSeqs.size === 0) return;
-    if (!window.confirm(`删除已选择的 ${selectedSeqs.size} 条消息？`)) return;
+    if (!(await requestConfirm({ message: `删除已选择的 ${selectedSeqs.size} 条消息？`, danger: true }))) return;
     topic.delMessagesList([...selectedSeqs], false);
     exitSelectMode();
   };

web/src/features/messages/DetailColumn.tsx

@@ -21,6 +21,8 @@ import type { MediaType } from '@/lib/api/messages';
 import { avatarBgClass, avatarLetter } from '@/lib/avatar';
 import { useTinode } from '@/lib/tinode/hooks';
 import { useCallStore } from '@/stores/calls';
+import { requestConfirm } from '@/stores/confirmDialog';
+import { notify } from '@/stores/globalToast';
 
 interface DetailColumnProps {
   topicId: string;
@@ -126,18 +128,18 @@ export function DetailColumn({ topicId, peerName, onClose, onOpenHistory }: Deta
     onError: (err) => showError(err, '删除好友失败'),
   });
 
-  const clearHistory = () => {
-    if (!window.confirm('确定清空与该联系人的聊天记录吗？此操作仅清除本地记录，不影响对方。')) return;
+  const clearHistory = async () => {
+    if (!(await requestConfirm({ message: '确定清空与该联系人的聊天记录吗？此操作仅清除本地记录，不影响对方。', danger: true }))) return;
     tinode.getTopic(topicId).delMessagesAll(false);
   };
 
-  const startDeleteFriend = () => {
-    if (!window.confirm(`确定删除好友 ${peerName} 吗？`)) return;
+  const startDeleteFriend = async () => {
+    if (!(await requestConfirm({ message: `确定删除好友 ${peerName} 吗？`, danger: true }))) return;
     deleteFriendMutation.mutate();
   };
 
   const reportAbuse = () => {
-    window.alert('该功能暂未开放，如需投诉举报请联系客服。');
+    notify('该功能暂未开放，如需投诉举报请联系客服。');
   };
 
   return (

web/src/features/messages/HistorySearchModal.tsx

@@ -10,6 +10,8 @@ import { avatarBgClass, avatarLetter } from '@/lib/avatar';
 import { useAuthedBlobUrl, useDebouncedValue, useEscapeKey } from '@/lib/hooks';
 import { renderDrafty } from '@/lib/messages/drafty';
 import { formatEventTimestamp } from '@/lib/messages/time';
+import { requestConfirm } from '@/stores/confirmDialog';
+import { notify } from '@/stores/globalToast';
 import { useMessageJumpStore } from '@/stores/messageJump';
 import { useSessionStore } from '@/stores/session';
 
@@ -90,14 +92,14 @@ function LinkResult({ item }: { item: SearchHit & { url?: string; title?: string
     try {
       result = await safetyCheck.mutateAsync(item.url!);
     } catch {
-      window.alert('链接安全检查失败，请稍后重试。');
+      notify('链接安全检查失败，请稍后重试。');
       return;
     }
     if (result.decision === 'block') {
-      window.alert('该链接存在安全风险，已被拦截。');
+      notify('该链接存在安全风险，已被拦截。');
       return;
     }
-    if (result.decision === 'warn' && !window.confirm('该链接可能存在风险，是否仍要打开？')) return;
+    if (result.decision === 'warn' && !(await requestConfirm({ message: '该链接可能存在风险，是否仍要打开？' }))) return;
     window.open(item.url, '_blank', 'noopener,noreferrer');
   };
 

web/src/features/messages/SafeLink.tsx

@@ -3,6 +3,8 @@ import type { ReactNode } from 'react';
 import { useMutation } from '@tanstack/react-query';
 
 import { checkUrlSafety } from '@/lib/api/security';
+import { requestConfirm } from '@/stores/confirmDialog';
+import { notify } from '@/stores/globalToast';
 
 /**
  * docs/IM-前后端对接文档.md:1822,1898 -- links found in chat content must pass a server-side risk
@@ -22,14 +24,14 @@ export function SafeLink({ href, children }: { href: string | undefined; childre
     try {
       result = await safetyCheck.mutateAsync(href);
     } catch {
-      window.alert('链接安全检查失败，请稍后重试。');
+      notify('链接安全检查失败，请稍后重试。');
       return;
     }
     if (result.decision === 'block') {
-      window.alert('该链接存在安全风险，已被拦截。');
+      notify('该链接存在安全风险，已被拦截。');
       return;
     }
-    if (result.decision === 'warn' && !window.confirm('该链接可能存在风险，是否仍要打开？')) return;
+    if (result.decision === 'warn' && !(await requestConfirm({ message: '该链接可能存在风险，是否仍要打开？' }))) return;
     window.open(href, '_blank', 'noopener,noreferrer');
   };
 

web/src/features/settings/GeneralSettingsPage.tsx

@@ -1,6 +1,7 @@
 import { useState } from 'react';
 
 import { Toast } from '@/app/Toast';
+import { requestConfirm } from '@/stores/confirmDialog';
 
 /**
  * README §8.7 mentions a "清空缓存「126 MB」" row -- confirmed no server endpoint touches cache at
@@ -16,7 +17,7 @@ export function GeneralSettingsPage() {
   const [error, setError] = useState('');
 
   const clearCache = async () => {
-    if (!window.confirm('确定清除本地缓存吗？不会影响你的账号数据。')) return;
+    if (!(await requestConfirm({ message: '确定清除本地缓存吗？不会影响你的账号数据。' }))) return;
     setStatus('clearing');
     try {
       if (typeof caches === 'undefined') throw new Error('此浏览器不支持缓存清除');

web/src/features/settings/SecuritySettingsPage.tsx

@@ -6,6 +6,7 @@ import { useNavigate } from 'react-router-dom';
 import { Icon } from '@/app/Icon';
 import { Toast } from '@/app/Toast';
 import { getTinode, resetTinode } from '@/lib/tinode/connection';
+import { requestConfirm } from '@/stores/confirmDialog';
 import { useSessionStore } from '@/stores/session';
 
 /**
@@ -66,8 +67,8 @@ export function SecuritySettingsPage() {
 
   const deleteAccount = async () => {
     if (deletingAccount) return;
-    if (!window.confirm('注销账号将永久删除你的账号和全部数据，此操作不可恢复。确定继续吗？')) return;
-    if (!window.confirm('请再次确认：真的要注销账号吗？此操作立即生效，无法撤销。')) return;
+    if (!(await requestConfirm({ message: '注销账号将永久删除你的账号和全部数据，此操作不可恢复。确定继续吗？', danger: true }))) return;
+    if (!(await requestConfirm({ message: '请再次确认：真的要注销账号吗？此操作立即生效，无法撤销。', danger: true }))) return;
     setDeletingAccount(true);
     try {
       await getTinode().delCurrentUser(true);

web/src/features/settings/SettingsLayout.tsx

@@ -7,6 +7,8 @@ import { Avatar } from '@/app/Avatar';
 import { Icon } from '@/app/Icon';
 import { getMe } from '@/lib/api/profile';
 import { resetTinode } from '@/lib/tinode/connection';
+import { requestConfirm } from '@/stores/confirmDialog';
+import { notImplemented } from '@/stores/globalToast';
 import { useSessionStore } from '@/stores/session';
 
 const DIRECTORY = [
@@ -39,10 +41,6 @@ const MOBILE_SHORTCUTS = [
  * endpoints 404, matching the old app's own real implementation (tinode-web.jsx:1995-2038), which
  * never calls a server logout endpoint at all, just clears local token/session and disconnects.
  */
-function notImplemented() {
-  window.alert('该功能暂未开放，如需联系客服。');
-}
-
 export function SettingsLayout() {
   const location = useLocation();
   const navigate = useNavigate();
@@ -55,8 +53,8 @@ export function SettingsLayout() {
   // currently shows. Irrelevant at `md`+ (desktop always shows the one real sidebar).
   const [mobileSubView, setMobileSubView] = useState(false);
 
-  const logout = () => {
-    if (!window.confirm('确定退出登录吗？')) return;
+  const logout = async () => {
+    if (!(await requestConfirm({ message: '确定退出登录吗？' }))) return;
     setLoggingOut(true);
     resetTinode();
     sessionStorage.removeItem('im-session-token');

web/src/stores/confirmDialog.ts

@@ -0,0 +1,48 @@
+import { create } from 'zustand';
+
+/**
+ * Replaces `window.confirm()` app-wide (README's own design language never intended a native
+ * browser dialog to show up inside this UI -- it was just the fastest way to gate a destructive
+ * action while the real dialog didn't exist yet). A global store + a single `<ConfirmDialogRoot>`
+ * mounted once at the app root (see App.tsx), not a local `useState` per call site: this needs to be
+ * callable from any event handler, including ones with no natural "own a piece of JSX for this"
+ * home (e.g. GroupFilesModal's per-row delete button), the same reasoning `stores/calls.ts`/
+ * `stores/messageJump.ts` already established for other "any component, any time" actions.
+ *
+ * `requestConfirm()` returns a Promise the same shape `window.confirm()`'s return value has (resolves
+ * true/false, never rejects) so every existing `if (!window.confirm(...)) return;` call site becomes
+ * `if (!(await requestConfirm({ message: ... }))) return;` with the enclosing function marked async --
+ * a mechanical, low-risk edit, not a rewrite of the surrounding logic.
+ */
+export interface ConfirmOptions {
+  title?: string;
+  message: string;
+  confirmLabel?: string;
+  cancelLabel?: string;
+  /** Red confirm button for irreversible/destructive actions (delete, disband, deregister) --
+   *  omitted (default blue) for merely consequential ones (log out, switch tenant). */
+  danger?: boolean;
+}
+
+interface PendingConfirm extends ConfirmOptions {
+  resolve: (value: boolean) => void;
+}
+
+interface ConfirmDialogState {
+  pending: PendingConfirm | null;
+  respond: (value: boolean) => void;
+}
+
+export const useConfirmDialogStore = create<ConfirmDialogState>((set, get) => ({
+  pending: null,
+  respond: (value) => {
+    get().pending?.resolve(value);
+    set({ pending: null });
+  },
+}));
+
+export function requestConfirm(options: ConfirmOptions): Promise<boolean> {
+  return new Promise((resolve) => {
+    useConfirmDialogStore.setState({ pending: { ...options, resolve } });
+  });
+}

web/src/stores/globalToast.ts

@@ -0,0 +1,37 @@
+import { create } from 'zustand';
+
+/**
+ * Replaces `window.alert()` app-wide, same rationale as `stores/confirmDialog.ts`'s replacement of
+ * `window.confirm()`: a global store + a single `<GlobalToastRoot>` mounted once at the app root
+ * renders the app's own existing `Toast` component (already used everywhere for a mutation's error
+ * state) instead of the browser's native dialog. `notify()` is deliberately fire-and-forget (no
+ * Promise, no return value) -- an alert-style message never blocked on a user response the way
+ * confirm did, so there's nothing to await.
+ */
+interface GlobalToastState {
+  message: string;
+  variant: 'success' | 'error';
+  token: number;
+}
+
+export const useGlobalToastStore = create<GlobalToastState>(() => ({
+  message: '',
+  variant: 'error',
+  token: 0,
+}));
+
+export function notify(message: string, variant: 'success' | 'error' = 'error') {
+  // `token` (not just `message`) is what Toast's own auto-dismiss effect keys off of via the caller
+  // -- see GlobalToastRoot -- so firing the SAME message twice in a row (e.g. two clicks on a
+  // still-disabled "该功能暂未开放" button before the first toast dismisses) restarts the timer
+  // instead of the second call being a no-op change that React skips re-rendering for.
+  useGlobalToastStore.setState((s) => ({ message, variant, token: s.token + 1 }));
+}
+
+/** Every existing `window.alert('该功能暂未开放，如需联系客服。')` call site (settings, composer
+ *  toolbar, add-friend, group/contact detail panels) used the identical hand-typed Chinese string --
+ *  one shared helper instead of that string living independently in five files that could each drift
+ *  from the others if the wording ever needs to change. */
+export function notImplemented() {
+  notify('该功能暂未开放，如需联系客服。');
+}