fix: 修复公告关闭功能 - 当次关闭与永久关闭区分

问题：不管选择"当次关闭"还是"永久关闭"，都会永久关闭公告

修复：
- 当次关闭：使用 sessionStorage + pageToken
  - pageToken 基于 performance.timeOrigin 生成
  - 刷新页面后 token 变化，公告重新显示
- 永久关闭：使用 localStorage
  - 持久化存储，刷新/重开后不再显示

修改文件：
- app-frontend/src/layouts/AppLayout.vue
- templates/index.html

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

templates/index.html

@@ -1055,24 +1055,39 @@
                 });
         }
 
-        let currentAnnouncementId = null;
+	        let currentAnnouncementId = null;
+	        const announcementPageToken = (() => {
+	            try {
+	                const timeOrigin = window.performance?.timeOrigin;
+	                if (typeof timeOrigin === 'number' && Number.isFinite(timeOrigin)) return String(timeOrigin);
+	            } catch (e) {
+	                // ignore
+	            }
+	            return String(Date.now());
+	        })();
 
-        async function checkAnnouncement() {
-            try {
-                const response = await fetch('/api/announcements/active');
-                if (!response.ok) return;
+	        async function checkAnnouncement() {
+	            try {
+	                const response = await fetch('/api/announcements/active');
+	                if (!response.ok) return;
                 const data = await response.json();
                 const announcement = data?.announcement;
                 if (!announcement || !announcement.id) return;
 
-                const sessionKey = `announcement_closed_${announcement.id}`;
-                try {
-                    if (sessionStorage.getItem(sessionKey)) return;
-                } catch (e) {
-                    // ignore
-                }
+	                const permanentKey = `announcement_closed_${announcement.id}`;
+	                const onceKey = `announcement_closed_once_${announcement.id}`;
+	                try {
+	                    if (localStorage.getItem(permanentKey) === '1') return;
+	                } catch (e) {
+	                    // ignore
+	                }
+	                try {
+	                    if (sessionStorage.getItem(onceKey) === announcementPageToken) return;
+	                } catch (e) {
+	                    // ignore
+	                }
 
-                currentAnnouncementId = announcement.id;
+	                currentAnnouncementId = announcement.id;
                 const titleEl = document.getElementById('announcementModalTitle');
                 const contentEl = document.getElementById('announcementModalContent');
                 if (titleEl) titleEl.textContent = announcement.title || '系统公告';
@@ -1083,29 +1098,34 @@
             }
         }
 
-        function closeAnnouncementOnce() {
-            if (currentAnnouncementId) {
-                try {
-                    sessionStorage.setItem(`announcement_closed_${currentAnnouncementId}`, '1');
-                } catch (e) {
-                    // ignore
-                }
-            }
-            closeModal('announcementModal');
-        }
+	        function closeAnnouncementOnce() {
+	            if (currentAnnouncementId) {
+	                try {
+	                    sessionStorage.setItem(`announcement_closed_once_${currentAnnouncementId}`, announcementPageToken);
+	                } catch (e) {
+	                    // ignore
+	                }
+	            }
+	            closeModal('announcementModal');
+	        }
 
-        async function dismissAnnouncementPermanently() {
-            if (!currentAnnouncementId) {
-                closeModal('announcementModal');
-                return;
-            }
-            try {
-                await fetch(`/api/announcements/${currentAnnouncementId}/dismiss`, { method: 'POST' });
-            } catch (e) {
-                // ignore
-            }
-            closeAnnouncementOnce();
-        }
+	        async function dismissAnnouncementPermanently() {
+	            if (!currentAnnouncementId) {
+	                closeModal('announcementModal');
+	                return;
+	            }
+	            try {
+	                localStorage.setItem(`announcement_closed_${currentAnnouncementId}`, '1');
+	            } catch (e) {
+	                // ignore
+	            }
+	            try {
+	                await fetch(`/api/announcements/${currentAnnouncementId}/dismiss`, { method: 'POST' });
+	            } catch (e) {
+	                // ignore
+	            }
+	            closeAnnouncementOnce();
+	        }
         document.addEventListener('DOMContentLoaded', function() {
             initTabs();
             loadVipStatus();