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/budget_support.py

@@ -310,6 +310,14 @@ class BudgetSupportMixin:
             }
 
         balance = self.get_balance(allocation)
+        reservation_source_type = self._reservation_source_type_from_claim(claim)
+        current_reservation = self._find_active_reservation(
+            source_type=reservation_source_type,
+            source_id=claim.id,
+        )
+        current_reserved_amount = self._money(
+            current_reservation.amount if current_reservation is not None else Decimal("0.00")
+        )
         over_budget_amount = max(amount - balance.available_amount, Decimal("0.00"))
         return {
             "matched": True,
@@ -319,6 +327,7 @@ class BudgetSupportMixin:
             "claim_amount": str(amount),
             "total_amount": str(balance.total_amount),
             "reserved_amount": str(balance.reserved_amount),
+            "current_reserved_amount": str(current_reserved_amount),
             "consumed_amount": str(balance.consumed_amount),
             "available_amount": str(balance.available_amount),
             "usage_rate": str(balance.usage_rate),
@@ -335,6 +344,14 @@ class BudgetSupportMixin:
             "project_code": allocation.project_code,
         }
 
+    @staticmethod
+    def _reservation_source_type_from_claim(claim: ExpenseClaim) -> str:
+        claim_no = str(claim.claim_no or "").strip().upper()
+        expense_type = str(claim.expense_type or "").strip().lower()
+        if claim_no.startswith(("AP-", "APP-")) or expense_type == "application" or expense_type.endswith("_application"):
+            return "application"
+        return "claim"
+
     def _find_allocation_for_claim(self, claim: ExpenseClaim) -> BudgetAllocation | None:
         fiscal_year, period_key = self._period_from_claim(claim)
         return self._find_allocation_for_dimension(