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/tests/test_applicant_expense_profile_algorithm.py

@@ -0,0 +1,74 @@
+from decimal import Decimal
+
+from app.algorithem import ApplicantExpenseProfileInput, evaluate_applicant_expense_profile
+
+
+def test_applicant_profile_recommends_review_and_days_cap() -> None:
+    result = evaluate_applicant_expense_profile(
+        ApplicantExpenseProfileInput(
+            applicant_claim_count_90d=6,
+            peer_claim_count_p75_90d=4,
+            applicant_amount_90d=Decimal("42800"),
+            available_peer_budget_90d=Decimal("150000"),
+            amount_percentile=Decimal("88"),
+            peer_amount_median_90d=Decimal("25000"),
+            adjusted_or_returned_count_180d=3,
+            approved_claim_count_180d=12,
+            requested_days=Decimal("5"),
+            peer_travel_days_p75=Decimal("3"),
+            business_buffer_days=Decimal("1"),
+            claim_amount=Decimal("8000"),
+            peer_daily_cost_baseline=Decimal("1400"),
+            tolerance_factor=Decimal("1.20"),
+        )
+    )
+
+    assert result.profile_score == 68
+    assert result.profile_level == "review"
+    assert result.recommendation_level == "review"
+    assert result.travel_days_ratio == Decimal("1.6667")
+    assert result.suggested_days == Decimal("4.0000")
+    assert result.suggested_amount_cap == Decimal("6720.00")
+    assert "applicant.amount_percentile.p85" in result.basis_codes
+    assert "travel.days_ratio.review" in result.basis_codes
+
+
+def test_applicant_profile_handles_missing_baselines_without_false_risk() -> None:
+    result = evaluate_applicant_expense_profile(
+        ApplicantExpenseProfileInput(
+            applicant_claim_count_90d=1,
+            applicant_amount_90d=Decimal("800"),
+            requested_days=Decimal("2"),
+            claim_amount=Decimal("800"),
+        )
+    )
+
+    assert result.profile_score == 0
+    assert result.profile_level == "normal"
+    assert result.recommendation_level == "normal"
+    assert result.frequency_ratio == Decimal("0")
+    assert result.daily_cost_ratio == Decimal("0")
+    assert result.suggested_days == Decimal("2.0000")
+    assert result.suggested_amount_cap is None
+    assert result.basis_codes == []
+
+
+def test_entertainment_deviation_can_escalate_recommendation() -> None:
+    result = evaluate_applicant_expense_profile(
+        ApplicantExpenseProfileInput(
+            entertainment_amount=Decimal("3000"),
+            attendee_count=3,
+            entertainment_standard_cap=Decimal("600"),
+            same_customer_frequency_90d=3,
+            applicant_entertainment_percentile=Decimal("96"),
+        )
+    )
+
+    assert result.entertainment_deviation_score == 100
+    assert result.current_claim_deviation_score == 100
+    assert result.profile_score == 15
+    assert result.profile_level == "normal"
+    assert result.recommendation_level == "escalation"
+    assert "entertainment.per_capita.escalation" in result.basis_codes
+    assert "entertainment.same_customer.frequency_review" in result.basis_codes
+    assert "entertainment.amount_percentile.p95" in result.basis_codes