fix(ui): [UI7-2] 统一全局 Design Tokens，移除冗余字体，修复异常色值引用

client/src/pages/NotificationsPage.tsx

@@ -102,7 +102,7 @@ export function NotificationsPage() {
             </TabsList>
           </Tabs>
 
-          <div className="text-sm text-slate-600">
+          <div className="text-sm text-zinc-600">
             未读 {listQuery.data?.unreadCount ?? 0} 条
           </div>
         </div>
@@ -122,7 +122,7 @@ export function NotificationsPage() {
         ) : null}
 
         {!listQuery.isLoading && !listQuery.isError ? (
-          <div className="rounded-lg border border-slate-200">
+          <div className="rounded-lg border border-zinc-200">
             <Table data-testid="notifications-table">
               <TableHeader>
                 <tr>
@@ -139,15 +139,15 @@ export function NotificationsPage() {
                     return (
                       <TableRow data-testid="notification-row" key={item.id}>
                         <TableCell>
-                          <div className="font-medium text-slate-900">{item.title}</div>
+                          <div className="font-medium text-zinc-900">{item.title}</div>
                           {item.body ? (
-                            <div className="mt-1 text-xs text-slate-500">{item.body}</div>
+                            <div className="mt-1 text-xs text-zinc-500">{item.body}</div>
                           ) : null}
                         </TableCell>
-                        <TableCell className="text-xs text-slate-600">
+                        <TableCell className="text-xs text-zinc-600">
                           {item.createdAt.slice(0, 19).replace("T", " ")}
                         </TableCell>
-                        <TableCell className="text-xs text-slate-600">
+                        <TableCell className="text-xs text-zinc-600">
                           {item.readAt ? "已读" : "未读"}
                         </TableCell>
                         <TableCell>
@@ -177,7 +177,7 @@ export function NotificationsPage() {
                   })
                 ) : (
                   <TableRow>
-                    <TableCell className="py-3 text-slate-500" colSpan={4}>
+                    <TableCell className="py-3 text-zinc-500" colSpan={4}>
                       暂无通知
                     </TableCell>
                   </TableRow>