fix(announcements): use proper empty-state copy instead of error message

frontend/src/i18n/locales/en/admin/resources.ts

@@ -375,6 +375,7 @@ export default {
     announcements: {
       title: 'Announcements',
       description: 'Create announcements and target by conditions',
+      createFirstAnnouncement: 'No announcements yet. Create your first one.',
       createAnnouncement: 'Create Announcement',
       editAnnouncement: 'Edit Announcement',
       deleteAnnouncement: 'Delete Announcement',

frontend/src/i18n/locales/zh/admin/resources.ts

@@ -372,6 +372,7 @@ export default {
     announcements: {
       title: '公告管理',
       description: '创建公告并按条件投放',
+      createFirstAnnouncement: '还没有公告，创建您的第一条公告。',
       createAnnouncement: '创建公告',
       editAnnouncement: '编辑公告',
       deleteAnnouncement: '删除公告',

frontend/src/views/admin/AnnouncementsView.vue

@@ -141,7 +141,7 @@
           <template #empty>
             <EmptyState
               :title="t('empty.noData')"
-              :description="t('admin.announcements.failedToLoad')"
+              :description="t('admin.announcements.createFirstAnnouncement')"
               :action-text="t('admin.announcements.createAnnouncement')"
               @action="openCreateDialog"
             />