feat(messaging,announcements): 前端 UI 集成星标/草稿/置顶/已读回执

- 消息星标：MessageList 卡片星标按钮（乐观更新+回滚）、MessageDetail 头部星标切换
- 消息草稿：MessageCompose 自动保存（2s 防抖）+ 手动保存按钮 + 状态指示器 + 发送后清理草稿
- 公告置顶：AnnouncementCard 管理端置顶按钮、AnnouncementDetail 置顶切换、置顶 Badge
- 公告已读回执：用户端详情页自动标记已读 + 已读/未读 Badge、管理端已读人数显示
- i18n：新增 announcements.meta.readCount 翻译键

src/modules/messaging/components/message-detail.tsx

@@ -5,17 +5,17 @@ import Link from "next/link"
 import { useRouter } from "next/navigation"
 import { toast } from "sonner"
 import { useTranslations } from "next-intl"
-import { ArrowLeft, Mail, Reply, Trash2 } from "lucide-react"
+import { ArrowLeft, Mail, Reply, Star, Trash2 } from "lucide-react"
 
 import { Badge } from "@/shared/components/ui/badge"
 import { Button } from "@/shared/components/ui/button"
 import { Card, CardContent, CardHeader, CardTitle } from "@/shared/components/ui/card"
 import { ConfirmDeleteDialog } from "@/shared/components/ui/confirm-delete-dialog"
-import { formatDate } from "@/shared/lib/utils"
+import { cn, formatDate } from "@/shared/lib/utils"
 import { usePermission } from "@/shared/hooks/use-permission"
 import { Permissions } from "@/shared/types/permissions"
 
-import { deleteMessageAction } from "../actions"
+import { deleteMessageAction, toggleMessageStarAction } from "../actions"
 import type { Message } from "../types"
 
 export function MessageDetail({
@@ -31,6 +31,8 @@ export function MessageDetail({
   const router = useRouter()
   const [isWorking, setIsWorking] = useState(false)
   const [deleteOpen, setDeleteOpen] = useState(false)
+  const [isStarred, setIsStarred] = useState(message.isStarred)
+  const [isTogglingStar, setIsTogglingStar] = useState(false)
   const { hasPermission } = usePermission()
   const canSend = hasPermission(Permissions.MESSAGE_SEND)
   const canDelete = hasPermission(Permissions.MESSAGE_DELETE)
@@ -58,6 +60,29 @@ export function MessageDetail({
     }
   }
 
+  const handleToggleStar = async () => {
+    setIsTogglingStar(true)
+    const prevStarred = isStarred
+    // 乐观更新
+    setIsStarred(!prevStarred)
+    try {
+      const res = await toggleMessageStarAction(message.id)
+      if (res.success) {
+        toast.success(t("messages.starToggled"))
+      } else {
+        // 回滚
+        setIsStarred(prevStarred)
+        toast.error(res.message)
+      }
+    } catch {
+      // 回滚
+      setIsStarred(prevStarred)
+      toast.error(t("messages.sendFailed"))
+    } finally {
+      setIsTogglingStar(false)
+    }
+  }
+
   const replyHref = canSend
     ? `/messages/compose?parentId=${message.id}&receiverId=${isReceived ? message.senderId : message.receiverId}&subject=${encodeURIComponent(
         message.subject?.startsWith("Re:") ? message.subject : `Re: ${message.subject ?? ""}`
@@ -76,6 +101,16 @@ export function MessageDetail({
           <h2 className="text-2xl font-bold tracking-tight">{t("title.detail")}</h2>
         </div>
         <div className="flex flex-wrap items-center gap-2">
+          <Button
+            onClick={handleToggleStar}
+            disabled={isTogglingStar}
+            variant={isStarred ? "default" : "outline"}
+          >
+            <Star
+              className={cn("mr-2 h-4 w-4", isStarred && "fill-current")}
+            />
+            {isStarred ? t("actions.unstar") : t("actions.star")}
+          </Button>
           {canSend ? (
             <Button asChild variant="outline">
               <Link href={replyHref ?? "#"}>
@@ -104,6 +139,12 @@ export function MessageDetail({
             ) : (
               <Badge variant="outline">{t("status.sent")}</Badge>
             )}
+            {isStarred ? (
+              <span className="inline-flex items-center gap-1 text-xs text-yellow-600">
+                <Star className="h-3.5 w-3.5 fill-yellow-400 text-yellow-400" aria-hidden="true" />
+                {t("actions.star")}
+              </span>
+            ) : null}
           </div>
           <CardTitle className="text-2xl">{message.subject ?? t("meta.noSubject")}</CardTitle>
           <div className="flex flex-wrap items-center gap-2 text-xs text-muted-foreground">