feat: 增强风险规则生成引擎与预算中心页面

后端拆分风险规则生成为解释器、语义分析、本体对齐等子模块，
优化模板执行和流程图生成，完善员工种子数据和导入逻辑，增强
报销单权限策略和草稿持久化，前端新增预算中心视图和趋势图
组件，重构审计页面和风险规则测试对话框交互，完善文档中心
和报销创建页面细节，补充单元测试覆盖。

server/tests/test_document_numbering.py

@@ -0,0 +1,94 @@
+from __future__ import annotations
+
+from datetime import UTC, datetime
+from decimal import Decimal
+
+import pytest
+from sqlalchemy import create_engine
+from sqlalchemy.orm import Session, sessionmaker
+from sqlalchemy.pool import StaticPool
+
+from app.db.base import Base
+from app.models.financial_record import ExpenseClaim
+from app.services.document_numbering import (
+    build_document_number,
+    generate_unique_expense_claim_no,
+    is_application_claim_no,
+)
+
+
+def build_session() -> Session:
+    engine = create_engine(
+        "sqlite+pysqlite:///:memory:",
+        connect_args={"check_same_thread": False},
+        poolclass=StaticPool,
+    )
+    Base.metadata.create_all(bind=engine)
+    factory = sessionmaker(bind=engine, autoflush=False, autocommit=False)
+    return factory()
+
+
+def test_build_document_number_uses_kind_prefix_timestamp_and_token() -> None:
+    timestamp = datetime(2026, 5, 25, 10, 30, 45, tzinfo=UTC)
+
+    assert (
+        build_document_number("application", timestamp=timestamp, token="ABCDEFGH")
+        == "AP-20260525103045-ABCDEFGH"
+    )
+    assert (
+        build_document_number("reimbursement", timestamp=timestamp, token="ABCDEFGH")
+        == "RE-20260525103045-ABCDEFGH"
+    )
+    assert (
+        build_document_number("audit", timestamp=timestamp, token="ABCDEFGH")
+        == "AD-20260525103045-ABCDEFGH"
+    )
+
+
+def test_build_document_number_rejects_ambiguous_token_chars() -> None:
+    timestamp = datetime(2026, 5, 25, 10, 30, 45, tzinfo=UTC)
+
+    with pytest.raises(ValueError):
+        build_document_number("application", timestamp=timestamp, token="ABCDEF10")
+
+
+def test_generate_unique_expense_claim_no_retries_existing_candidate() -> None:
+    timestamp = datetime(2026, 5, 25, 10, 30, 45, tzinfo=UTC)
+    with build_session() as db:
+        db.add(
+            ExpenseClaim(
+                claim_no="RE-20260525103045-ABCDEFGH",
+                employee_name="张三",
+                department_name="市场部",
+                project_code=None,
+                expense_type="transport",
+                reason="交通报销",
+                location="深圳",
+                amount=Decimal("10.00"),
+                currency="CNY",
+                invoice_count=1,
+                occurred_at=timestamp,
+                status="draft",
+                approval_stage="待提交",
+                risk_flags_json=[],
+            )
+        )
+        db.commit()
+
+        tokens = iter(["ABCDEFGH", "HGFEDCBA"])
+
+        assert (
+            generate_unique_expense_claim_no(
+                db,
+                "reimbursement",
+                timestamp=timestamp,
+                token_factory=lambda: next(tokens),
+            )
+            == "RE-20260525103045-HGFEDCBA"
+        )
+
+
+def test_is_application_claim_no_supports_new_and_legacy_prefixes() -> None:
+    assert is_application_claim_no("AP-20260525103045-ABCDEFGH")
+    assert is_application_claim_no("APP-20260525-ABC123")
+    assert not is_application_claim_no("RE-20260525103045-ABCDEFGH")