feat(web): 设置中心缓存管理与文件预览资产工具

- 新增 documentPreviewAssets 工具，统一从 URL/Blob/File 推断预览类型（image/pdf/file/unsupported）
- SettingsView/SettingsView.js/settingsModelHelper 新增系统缓存管理区块，调用 /settings/cache/clear 并展示清理结果；useSettings/services 适配
- WorkbenchAiFilePreviewDialog/useWorkbenchAiFilePreview 接入预览资产工具，workbenchAiComposerModel 调整文件处理
- ReceiptFolder/LogDetailView/DigitalEmployeeWorkRecords/travelReimbursementAttachmentModel 配套适配
- 新增 settings-cache-management-section 测试，更新 settings-llm/rendering/receipt-folder-view/composer-components/attachment-association 测试

web/src/composables/useSettings.js

@@ -3,7 +3,7 @@ import { useRoute, useRouter } from 'vue-router'
 
 import { useSystemState } from './useSystemState.js'
 import { useThemeSkin } from './useThemeSkin.js'
-import { fetchSettings, saveSettings } from '../services/settings.js'
+import { clearSystemCaches, fetchSettings, saveSettings } from '../services/settings.js'
 import { useToast } from './useToast.js'
 import {
   isHermesEmployeeSettingsReady
@@ -56,6 +56,10 @@ export function useSettings() {
   const sessionRetentionPickerOpen = ref(false)
   const sessionRetentionPickerRef = ref(null)
   const logoInputRef = ref(null)
+  const cacheClearing = ref(false)
+  const cacheClearItems = ref([])
+  const cacheClearMessage = ref('')
+  const cacheClearFailed = ref(false)
 
   const sections = SECTION_DEFINITIONS
   const logLevels = LOG_LEVELS
@@ -433,6 +437,46 @@ export function useSettings() {
     })
   }
 
+  function normalizeCacheClearErrorMessage(error) {
+    const message = String(error?.message || '').trim()
+
+    if (!message || /^not found$/i.test(message)) {
+      return '缓存清理接口暂不可用，请确认后端服务已加载最新路由后重试。'
+    }
+
+    return message
+  }
+
+  async function clearAllCaches() {
+    if (cacheClearing.value) {
+      return
+    }
+
+    cacheClearing.value = true
+    cacheClearMessage.value = ''
+    cacheClearItems.value = []
+    cacheClearFailed.value = false
+
+    try {
+      const payload = await clearSystemCaches()
+      const items = Array.isArray(payload?.items) ? payload.items : []
+      const totalCleared = Number(payload?.totalCleared || 0)
+      cacheClearItems.value = items
+      cacheClearMessage.value = totalCleared > 0
+        ? `已清理 ${totalCleared} 条缓存。`
+        : '当前没有可清理的缓存。'
+      cacheClearFailed.value = false
+      toast(cacheClearMessage.value)
+    } catch (error) {
+      const message = normalizeCacheClearErrorMessage(error)
+      cacheClearFailed.value = true
+      cacheClearMessage.value = message
+      toast(message)
+    } finally {
+      cacheClearing.value = false
+    }
+  }
+
   async function saveMailSection() {
     const mailForm = pageState.value.mailForm
 
@@ -494,6 +538,10 @@ export function useSettings() {
       return
     }
 
+    if (activeSection.value === 'cacheManagement') {
+      return
+    }
+
     if (activeSection.value === 'rendering') {
       await saveRenderingSection()
       return
@@ -557,6 +605,11 @@ export function useSettings() {
     activeThemeSkinId,
     archiveCycleOptions,
     activateSection,
+    cacheClearFailed,
+    cacheClearItems,
+    cacheClearMessage,
+    cacheClearing,
+    clearAllCaches,
     clearRenderSecretMask,
     completedSectionCount,
     logLevels,