feat: 增加差旅报销标准测算和财务终审流程

新增差旅报销测算接口及 Spreadsheet 规则解析，审批流程拆分
直属领导审批与财务终审两阶段并细分权限，修复 PDF 文本层
缺失时自动回退 OCR，提交后清理关联会话，前端适配审批流
交互并补充单元测试。

server/storage/knowledge/.index.json

@@ -20,7 +20,7 @@
       "ingest_document_name": "远光《公司支出管理办法（2024）》.pdf",
       "ingest_document_updated_at": "2026-05-17T09:28:28.999515+00:00",
       "ingest_document_sha256": "67a74538bce0dec71ccbb947256cc2c9c0e672d148de49406b967ae1379dbece",
-      "ingest_agent_run_id": "run_8b0ead1e3c734a53"
+      "ingest_agent_run_id": "run_3a0b0ecb941b4c8e"
     },
     {
       "id": "a8f8465df08e455ebe133351721d49f8",
@@ -36,12 +36,12 @@
       "uploaded_by": "admin",
       "version_number": 1,
       "ingest_status": 4,
-      "ingest_status_updated_at": "2026-05-19T16:00:57.418443+00:00",
+      "ingest_status_updated_at": "2026-05-20T16:00:02.515903+00:00",
       "ingest_completed_at": "",
       "ingest_document_name": "",
       "ingest_document_updated_at": "",
       "ingest_document_sha256": "",
-      "ingest_agent_run_id": "run_57f2d8727aaa4374"
+      "ingest_agent_run_id": "run_3a0b0ecb941b4c8e"
     }
   ]
 }