feat: 完善知识库、策略预览与OnlyOffice集成

## 配置与环境
- .env.example: 更新环境变量配置
- docker-compose.yml: 完善Docker编排配置
- docker/README.md: 更新Docker文档

## 后端知识库模块
- endpoints/knowledge.py: 增强知识库API端点
- schemas/knowledge.py: 扩展知识库数据模型
- services/knowledge.py: 完善知识库业务逻辑
- config.py: 优化配置管理
- storage/knowledge/.index.json: 更新知识库索引

## 前端功能
- api.js: 完善API服务层
- knowledge.js: 优化知识库服务
- onlyoffice.js: 新增OnlyOffice文档服务集成
- TopBar.vue: 优化顶部导航栏
- PoliciesView.vue: 完善策略视图
- AppShellRouteView.vue: 新增应用外壳路由视图
- views/scripts/PoliciesView.js: 优化策略脚本
- policiesPreviewFormatters.js: 新增策略预览格式化工具

## 样式
- policies-view.css: 完善策略页样式

## 测试
- api-request.test.mjs: API请求测试
- onlyoffice-service.test.mjs: OnlyOffice服务测试
- policies-preview-formatters.test.mjs: 策略预览格式化测试

web/src/views/scripts/policiesPreviewFormatters.js

@@ -0,0 +1,65 @@
+function splitPreviewRow(line) {
+  return String(line || '')
+    .split('|')
+    .map((cell) => cell.trim())
+}
+
+export function buildPreviewMetaLine(document) {
+  if (!document) {
+    return []
+  }
+
+  return [document.summary, document.time].filter(Boolean)
+}
+
+export function buildPreviewSecondaryMetaLine(document, page = null) {
+  if (!document) {
+    return []
+  }
+
+  const activePage = page || (Array.isArray(document.previewPages) ? document.previewPages[0] : null)
+  if (!activePage) {
+    return []
+  }
+
+  const parts = []
+
+  if (activePage.subtitle) {
+    parts.push(activePage.subtitle)
+  }
+
+  if (document.previewKind === 'table') {
+    for (const item of activePage.stats || []) {
+      if (!item?.label || !item?.value || item.label === '文件大小') {
+        continue
+      }
+      parts.push(`${item.label} ${item.value}`)
+    }
+  }
+
+  return parts
+}
+
+export function buildExcelPreviewTable(page) {
+  const rawRows = (page?.blocks || [])
+    .flatMap((block) => block.lines || [])
+    .map(splitPreviewRow)
+    .filter((row) => row.length > 0 && row.some((cell) => cell !== ''))
+
+  if (!rawRows.length) {
+    return { headers: [], rows: [] }
+  }
+
+  const columnCount = rawRows.reduce((max, row) => Math.max(max, row.length), 0)
+  const normalizedRows = rawRows.map((row) =>
+    Array.from({ length: columnCount }, (_, index) => row[index] ?? '')
+  )
+
+  const [headerRow, ...bodyRows] = normalizedRows
+  const headers = headerRow.map((cell, index) => cell || `列 ${index + 1}`)
+
+  return {
+    headers,
+    rows: bodyRows
+  }
+}