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>

static/app/assets/auth-xwgKTSGk.js

@@ -0,0 +1 @@
+import{p as s}from"./index-CGLq5RWF.js";async function r(){const{data:a}=await s.get("/email/verify-status");return a}async function o(){const{data:a}=await s.post("/generate_captcha",{});return a}async function e(a){const{data:t}=await s.post("/login",a);return t}async function i(a){const{data:t}=await s.post("/register",a);return t}async function c(a){const{data:t}=await s.post("/resend-verify-email",a);return t}async function f(a){const{data:t}=await s.post("/forgot-password",a);return t}async function u(a){const{data:t}=await s.post("/reset-password-confirm",a);return t}export{f as a,i as b,u as c,r as f,o as g,e as l,c as r};