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/tests/settings-llm-section.test.mjs

@@ -1,17 +1,18 @@
 import assert from 'node:assert/strict'
 import { readFileSync } from 'node:fs'
 
-const settingsScript = readFileSync(new URL('../src/views/scripts/SettingsView.js', import.meta.url), 'utf8')
+const settingsModel = readFileSync(new URL('../src/utils/settingsModelHelper.js', import.meta.url), 'utf8')
 const settingsView = readFileSync(new URL('../src/views/SettingsView.vue', import.meta.url), 'utf8')
+const llmSettingsPanel = readFileSync(new URL('../src/views/LlmSettingsPanel.vue', import.meta.url), 'utf8')
 
 function testLlmSectionReplacesVlmWithReranker() {
   assert.doesNotMatch(settingsView, /VLM 模型/)
-  assert.match(settingsView, /Reranker 模型配置/)
-  assert.match(settingsScript, /rerankerProvider/)
+  assert.match(llmSettingsPanel, /Reranker 模型配置/)
+  assert.match(settingsModel, /rerankerProvider/)
 }
 
 function testRerankerCardRendersAfterEmbeddingCard() {
-  assert.match(settingsView, /Embedding 模型配置[\s\S]*Reranker 模型配置/)
+  assert.match(llmSettingsPanel, /Embedding 模型配置[\s\S]*Reranker 模型配置/)
 }
 
 function run() {