feat: 新增预算费控模型与报销审批流引擎

后端新增预算费控服务和报销单审批流模块，引入申请人费用画像
算法，优化知识库 RAG 运行时和同步逻辑，完善报销单工作流常
量和明细同步，更新差旅报销规则电子表格，前端新增预算分析
组件和数字员工模型，完善审批对话框和洞察面板交互，优化侧
边栏和顶栏样式，补充单元测试。

server/src/app/services/expense_claim_application_handoff.py

@@ -68,7 +68,10 @@ class ExpenseClaimApplicationHandoffMixin:
                     "application_claim_no": application_claim.claim_no,
                     "application_budget_amount": str(application_claim.amount or Decimal("0.00")),
                     "application_approval_event_id": str(approval_flag.get("approval_event_id") or ""),
-                    "leader_opinion": str(approval_flag.get("opinion") or "").strip(),
+                    "leader_opinion": str(
+                        approval_flag.get("leader_opinion") or approval_flag.get("opinion") or ""
+                    ).strip(),
+                    "budget_opinion": str(approval_flag.get("budget_opinion") or "").strip(),
                     "created_at": created_at.isoformat(),
                 }
             ],