refactor(announcements,messaging,notifications): V1+V2 审计重构 — i18n 命名空间独立 + 通知标题 i18n 化 + 服务端过滤 + 编排下沉 + 表单错误展示 + 架构图同步

V1 改进（已完成）:
- P0-4/P1-4/P1-5: 通知组件和 CRUD Action 从 messaging 迁移至 notifications 模块
- P1-5: 新增 getMessagesPageData / getAdminAnnouncementsPageData 编排函数
- P1-6: announcements schema 添加 superRefine 条件校验
- P1-7: 新增 useMessageSearch hook（防抖 + 请求竞态取消）+ 客户端分页 UI
- P1-9: deleteMessage 事务化
- P2-11: 全模块 trackEvent 埋点
- 全模块 i18n 接入 + Error Boundary + a11y 改进

V2 改进（本次完成）:
- V2-P0-1: 通知 i18n 命名空间独立（notifications.json），useTranslations 从 "messages" 切换到 "notifications"
- V2-P0-2: 公告/消息通知标题 i18n 化，Server Action 中使用 getTranslations 生成通知标题
- V2-P1-1: AnnouncementList 纯服务端过滤，移除客户端 useState/useMemo
- V2-P1-2: MessageList 客户端过滤仅在初始数据时执行，搜索结果由服务端按 tab 过滤
- V2-P1-3: 消息详情页编排下沉，新增 getMessageDetailPageData 编排函数
- V2-P1-4: 表单服务端校验错误展示（fieldErrors + aria-invalid）
- V2-P2-1: 轮询间隔常量化（POLL_INTERVAL_MS）
- V2-P2-2: 架构图同步（004 + 005）

src/modules/announcements/actions.ts

@@ -2,8 +2,10 @@
 
 import { revalidatePath } from "next/cache"
 import { createId } from "@paralleldrive/cuid2"
+import { getTranslations } from "next-intl/server"
 
 import { requirePermission, PermissionDeniedError } from "@/shared/lib/auth-guard"
+import { trackEvent } from "@/shared/lib/track-event"
 import { Permissions } from "@/shared/types/permissions"
 import type { ActionState } from "@/shared/types/action-state"
 import { sendBatchNotifications } from "@/modules/notifications"
@@ -69,10 +71,14 @@ async function notifyAnnouncementPublished(announcement: Announcement): Promise<
     const targetUserIds = await resolveTargetUserIds(announcement)
     if (targetUserIds.length === 0) return
 
+    const t = await getTranslations("announcements")
+    const title = t("notification.publishedTitle", { title: announcement.title })
+    const content = t("notification.publishedContent")
+
     const payloads: NotificationPayload[] = targetUserIds.map((userId) => ({
       userId,
-      title: `新公告：${announcement.title}`,
-      content: announcement.content.slice(0, 200),
+      title,
+      content,
       type: "info",
       actionUrl: `/announcements/${announcement.id}`,
       metadata: {
@@ -146,6 +152,14 @@ export async function createAnnouncementAction(
     revalidatePath("/admin/announcements")
     revalidatePath("/announcements")
 
+    void trackEvent({
+      event: isPublished ? "announcement.published" : "announcement.created",
+      userId: ctx.userId,
+      targetId: id,
+      targetType: "announcement",
+      properties: { type: input.type, status: input.status },
+    })
+
     return { success: true, message: "Announcement created", data: id }
   } catch (e) {
     return handleActionError(e)
@@ -215,6 +229,13 @@ export async function updateAnnouncementAction(
     revalidatePath(`/admin/announcements/${id}`)
     revalidatePath("/announcements")
 
+    void trackEvent({
+      event: isPublished && !wasPublished ? "announcement.published" : "announcement.updated",
+      targetId: id,
+      targetType: "announcement",
+      properties: { type: input.type, status: input.status, wasPublished },
+    })
+
     return { success: true, message: "Announcement updated", data: id }
   } catch (e) {
     return handleActionError(e)
@@ -233,6 +254,13 @@ export async function deleteAnnouncementAction(id: string): Promise<ActionState<
     revalidatePath("/admin/announcements")
     revalidatePath("/announcements")
 
+    void trackEvent({
+      event: "announcement.deleted",
+      targetId: id,
+      targetType: "announcement",
+      properties: { type: existing.type, status: existing.status },
+    })
+
     return { success: true, message: "Announcement deleted" }
   } catch (e) {
     return handleActionError(e)
@@ -258,6 +286,13 @@ export async function publishAnnouncementAction(id: string): Promise<ActionState
     revalidatePath(`/admin/announcements/${id}`)
     revalidatePath("/announcements")
 
+    void trackEvent({
+      event: "announcement.published",
+      targetId: id,
+      targetType: "announcement",
+      properties: { type: existing.type },
+    })
+
     return { success: true, message: "Announcement published" }
   } catch (e) {
     return handleActionError(e)
@@ -277,6 +312,13 @@ export async function archiveAnnouncementAction(id: string): Promise<ActionState
     revalidatePath(`/admin/announcements/${id}`)
     revalidatePath("/announcements")
 
+    void trackEvent({
+      event: "announcement.archived",
+      targetId: id,
+      targetType: "announcement",
+      properties: { type: existing.type },
+    })
+
     return { success: true, message: "Announcement archived" }
   } catch (e) {
     return handleActionError(e)