fix: 修复系统设置的动态注入问题

- 创建 useSiteSettings composable 在应用启动时加载系统设置
- 从 window.__SITE_CONFIG__（后端注入）和 localStorage 初始化设置
- 修复 favicon 更新逻辑，正确移除旧 favicon 并添加新的
- 在路由守卫中设置页面标题，格式为 '页面名 - 网站名'
- 简化 admin.vue 和 admin-sidebar 组件，使用统一的设置管理

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/components/admin-sidebar/index.vue

@@ -1,13 +1,15 @@
 <script lang="ts" setup>
 import { Boxes, Code, CreditCard, DollarSign, FileLock, Gauge, GitBranch, HardDrive, Hash, Key, KeyRound, Mail, Megaphone, MessageSquare, Monitor, Network, Plug, ScrollText, Settings, Shield, Smartphone, Users, Variable } from 'lucide-vue-next'
-import { computed, onMounted, onUnmounted, reactive } from 'vue'
+import { computed, onMounted, onUnmounted, reactive, watch } from 'vue'
 import { useI18n } from 'vue-i18n'
 
 import NavTeam from '@/components/app-sidebar/nav-team.vue'
 import TeamSwitcher from '@/components/app-sidebar/team-switcher.vue'
 import NavFooter from '@/components/admin-sidebar/nav-footer.vue'
+import { useSiteSettings } from '@/composables/use-site-settings'
 
 const { t } = useI18n()
+const { siteSettings } = useSiteSettings()
 
 const user = reactive({
   name: t('nav.admin'),
@@ -16,48 +18,32 @@ const user = reactive({
   role: 'admin',
 })
 
-const siteSettings = reactive({
-  name: t('nav.adminDashboard'),
-  logo: '',
-})
-
 const teams = reactive([
   {
     name: t('nav.adminDashboard'),
-    logo: Code,
+    logo: Code as any,
   },
 ])
 
-function loadSystemSettings() {
-  const storedSettings = localStorage.getItem('systemSettings')
-  if (storedSettings) {
-    try {
-      const parsed = JSON.parse(storedSettings)
-      if (parsed.site_name) {
-        siteSettings.name = parsed.site_name
-        teams[0].name = parsed.site_name
-      }
-      if (parsed.site_logo) {
-        siteSettings.logo = parsed.site_logo
-        teams[0].logo = parsed.site_logo
-      }
-    }
-    catch (e) {
-      console.error('Failed to parse systemSettings from localStorage', e)
-    }
+// 监听系统设置变化
+watch(() => siteSettings.siteName, (newName) => {
+  if (newName) {
+    teams[0].name = newName
   }
-}
+})
 
-function handleSettingsChange(event: CustomEvent) {
-  const settings = event.detail
-  if (settings.site_name) {
-    siteSettings.name = settings.site_name
-    teams[0].name = settings.site_name
-  }
-  if (settings.site_logo) {
-    siteSettings.logo = settings.site_logo
-    teams[0].logo = settings.site_logo
+watch(() => siteSettings.siteLogo, (newLogo) => {
+  if (newLogo) {
+    teams[0].logo = newLogo
   }
+})
+
+// 初始化时设置
+if (siteSettings.siteName) {
+  teams[0].name = siteSettings.siteName
+}
+if (siteSettings.siteLogo) {
+  teams[0].logo = siteSettings.siteLogo
 }
 
 onMounted(() => {
@@ -74,13 +60,9 @@ onMounted(() => {
       console.error('Failed to parse user from localStorage', e)
     }
   }
-
-  loadSystemSettings()
-  window.addEventListener('system-settings-changed', handleSettingsChange as EventListener)
 })
 
 onUnmounted(() => {
-  window.removeEventListener('system-settings-changed', handleSettingsChange as EventListener)
 })
 
 const navMain = computed(() => [