feat: 重构报销单服务并完善前端提交与审核交互

重构 expense_claims 服务模块结构并优化差旅票据审核逻辑，
增强用户代理服务的票据类型识别，前端报销创建页面拆分为
附件模型和会话模型模块，重构提交编排器和草稿关联确认流
程，更新知识库索引，补充单元测试。

web/src/utils/markdown.js

@@ -6,7 +6,78 @@ const markdown = new MarkdownIt({
   breaks: true
 })
 
+const defaultTableOpen = markdown.renderer.rules.table_open
+const defaultTableClose = markdown.renderer.rules.table_close
+
+markdown.renderer.rules.table_open = (tokens, idx, options, env, self) => (
+  `<div class="markdown-table-wrap">${defaultTableOpen ? defaultTableOpen(tokens, idx, options, env, self) : '<table>'}`
+)
+
+markdown.renderer.rules.table_close = (tokens, idx, options, env, self) => (
+  `${defaultTableClose ? defaultTableClose(tokens, idx, options, env, self) : '</table>'}</div>`
+)
+
+const ALLOWED_COLON_HEADING_TITLES = new Set([
+  '基础信息识别结果',
+  '报销测算参考',
+  '补充信息'
+])
+
+function splitColonHeadingLine(line) {
+  const rawLine = String(line || '')
+  const trimmed = rawLine.trim()
+  if (!trimmed || trimmed.startsWith('|') || /^#{1,6}\s/.test(trimmed)) {
+    return [rawLine]
+  }
+
+  const chineseColonIndex = trimmed.indexOf('：')
+  const asciiColonIndex = trimmed.indexOf(':')
+  const colonIndexes = [chineseColonIndex, asciiColonIndex].filter((index) => index > 0)
+  if (!colonIndexes.length) {
+    return [rawLine]
+  }
+
+  const colonIndex = Math.min(...colonIndexes)
+  const title = trimmed.slice(0, colonIndex + 1)
+  const titleText = title.slice(0, -1)
+  const body = trimmed.slice(colonIndex + 1).trim()
+  if (!ALLOWED_COLON_HEADING_TITLES.has(titleText)) {
+    return [rawLine]
+  }
+
+  return body ? [`### ${title}`, '', body] : [`### ${title}`]
+}
+
+function normalizeColonHeadings(text) {
+  const lines = String(text || '').replace(/\r\n?/g, '\n').split('\n')
+  const normalizedLines = []
+  let inFence = false
+
+  lines.forEach((line) => {
+    if (/^\s*(```|~~~)/.test(line)) {
+      inFence = !inFence
+      normalizedLines.push(line)
+      return
+    }
+    if (inFence) {
+      normalizedLines.push(line)
+      return
+    }
+
+    const nextLines = splitColonHeadingLine(line)
+    if (nextLines[0]?.startsWith('### ') && normalizedLines.length) {
+      const previousLine = normalizedLines[normalizedLines.length - 1]
+      if (String(previousLine || '').trim()) {
+        normalizedLines.push('')
+      }
+    }
+    normalizedLines.push(...nextLines)
+  })
+
+  return normalizedLines.join('\n').replace(/\n{3,}/g, '\n\n')
+}
+
 export function renderMarkdown(text = '') {
-  const normalized = String(text || '').trim()
+  const normalized = normalizeColonHeadings(text).trim()
   return normalized ? markdown.render(normalized) : ''
 }