feat: 添加安全仪表板前端页面

- 新增 SecurityPage.vue: 统计卡片、威胁事件表格、封禁管理、风险查询
- 新增 api/security.js: 安全相关API封装
- 路由添加 /security 页面
- 侧边栏添加"安全防护"菜单项

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

static/admin/assets/email-DoKk83fr.js

@@ -0,0 +1 @@
+import{S as n}from"./index-CDhtYQo-.js";async function i(){const{data:a}=await n.get("/email/settings");return a}async function e(a){const{data:t}=await n.post("/email/settings",a);return t}async function c(){const{data:a}=await n.get("/email/stats");return a}async function o(a){const{data:t}=await n.get("/email/logs",{params:a});return t}async function l(a){const{data:t}=await n.post("/email/logs/cleanup",{days:a});return t}export{o as a,i as b,l as c,c as f,e as u};