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/tests/travel-reimbursement-review-drawer-switch.test.mjs

@@ -156,19 +156,19 @@ test('review drawer save action is disabled while receipt recognition is submitt
   )
 })
 
-test('draft creation waits for composer attachments to be persisted before leaving submit state', () => {
+test('draft creation starts composer attachment persistence after response rendering', () => {
   assert.match(
     submitComposerScript,
-    /try \{\s*await syncComposerFilesToDraft\(resolvedDraftClaimId, files\)\s*\} catch \(error\) \{/s
+    /void syncComposerFilesToDraft\(resolvedDraftClaimId, files\)\s*\.then\(\(\) => \{\s*persistSessionState\(\)\s*\}\)\s*\.catch\(\(error\) => \{/s
   )
   assert.doesNotMatch(
     submitComposerScript,
-    /syncComposerFilesToDraft\(resolvedDraftClaimId, files\)\.catch/
+    /await syncComposerFilesToDraft\(resolvedDraftClaimId, files\)/
   )
   assert.ok(
-    submitComposerScript.indexOf('await syncComposerFilesToDraft(resolvedDraftClaimId, files)') <
-      submitComposerScript.indexOf('submitting.value = false'),
-    'attachment persistence should finish before submit state is cleared'
+    submitComposerScript.indexOf('replaceMessage(pendingMessage.id, assistantMessage)') <
+      submitComposerScript.indexOf('void syncComposerFilesToDraft(resolvedDraftClaimId, files)'),
+    'assistant response should render before background attachment persistence starts'
   )
   assert.match(attachmentsScript, /function normalizeAttachmentMatchName\(value\)/)
   assert.match(attachmentsScript, /const normalizedMatchBuckets = new Map\(\)/)