feat: 新增风险规则生成引擎与知识图谱可视化

后端新增风险规则自动生成和模板执行服务，支持从规则资产
批量生成并持久化风险规则文件；知识库入库日志增强图谱
查询和本地 RAG 回退，前端审计页面增加风险规则模型和流
程图组件，知识入库面板拆分为图谱可视化子组件，报销创
建页面增加引导式流程模型，更新知识库索引数据。

server/tests/test_risk_rule_generation.py

@@ -0,0 +1,106 @@
+from __future__ import annotations
+
+import json
+
+from sqlalchemy import create_engine
+from sqlalchemy.orm import Session, sessionmaker
+from sqlalchemy.pool import StaticPool
+
+from app.core.agent_enums import AgentAssetDomain, AgentAssetStatus
+from app.db.base import Base
+from app.models.agent_asset import AgentAsset
+from app.schemas.agent_asset import AgentAssetRiskRuleGenerateRequest
+from app.services.agent_asset_rule_library import AgentAssetRuleLibraryManager
+from app.services.agent_asset_spreadsheet import RISK_RULES_LIBRARY
+from app.services.risk_rule_flow_diagram import RiskRuleFlowDiagramRenderer, RiskRuleFlowDiagramSpec
+from app.services.risk_rule_generation import RiskRuleGenerationService
+
+
+class NullRuntimeChatService:
+    def complete(self, *args, **kwargs) -> None:
+        return None
+
+
+def build_session() -> Session:
+    engine = create_engine(
+        "sqlite+pysqlite:///:memory:",
+        connect_args={"check_same_thread": False},
+        poolclass=StaticPool,
+    )
+    Base.metadata.create_all(bind=engine)
+    session_factory = sessionmaker(bind=engine, autoflush=False, autocommit=False)
+    return session_factory()
+
+
+def test_generate_risk_rule_asset_creates_draft_json_rule(tmp_path) -> None:
+    with build_session() as db:
+        service = RiskRuleGenerationService(
+            db,
+            rule_library_manager=AgentAssetRuleLibraryManager(rule_root=tmp_path / "rules"),
+            runtime_chat_service=NullRuntimeChatService(),
+        )
+
+        asset_id = service.generate_rule_asset(
+            AgentAssetRiskRuleGenerateRequest(
+                business_domain=AgentAssetDomain.EXPENSE,
+                risk_level="high",
+                natural_language="住宿城市必须出现在本次差旅行程城市中，否则提示高风险。",
+            ),
+            actor="pytest",
+        )
+
+        asset = db.get(AgentAsset, asset_id)
+        assert asset is not None
+        assert asset.status == AgentAssetStatus.DRAFT.value
+        assert asset.config_json["detail_mode"] == "json_risk"
+        assert asset.config_json["evaluator"] == "template_rule"
+        assert asset.current_version == "v0.1.0"
+
+        file_name = asset.config_json["rule_document"]["file_name"]
+        rule_path = tmp_path / "rules" / RISK_RULES_LIBRARY / file_name
+        payload = json.loads(rule_path.read_text(encoding="utf-8"))
+        assert payload["rule_code"] == asset.code
+        assert payload["outcomes"]["fail"]["severity"] == "high"
+        assert payload["template_key"] == "field_compare_v1"
+        assert payload["metadata"]["natural_language"].startswith("住宿城市")
+        assert payload["inputs"]["fields"]
+        assert payload["flow_diagram_svg"].startswith("<svg")
+        assert 'width="760" height="280"' in payload["flow_diagram_svg"]
+        assert 'data-risk-flow-style="review-node-only"' in payload["flow_diagram_svg"]
+        assert "RULE FLOW" in payload["flow_diagram_svg"]
+        assert "进入复核" in payload["flow_diagram_svg"]
+        assert "否" in payload["flow_diagram_svg"]
+        assert "是" in payload["flow_diagram_svg"]
+        assert "#dc2626" in payload["flow_diagram_svg"]
+        assert "#fecaca" in payload["flow_diagram_svg"]
+        assert "#10a37f" not in payload["flow_diagram_svg"]
+        assert "#f97316" not in payload["flow_diagram_svg"]
+        assert "feDropShadow" not in payload["flow_diagram_svg"]
+
+
+def test_risk_rule_flow_diagram_uses_risk_level_palette() -> None:
+    renderer = RiskRuleFlowDiagramRenderer()
+
+    def render(severity: str, label: str) -> str:
+        return renderer.render(
+            RiskRuleFlowDiagramSpec(
+                title="测试规则",
+                domain_label="报销",
+                severity=severity,
+                severity_label=label,
+                fields=(),
+                start="业务单据提交",
+                evidence="读取规则字段",
+                decision="判断是否命中风险",
+                basis="根据规则字段判断",
+                pass_text="未命中风险，继续流转",
+                fail_text=f"命中{label}，进入复核",
+            )
+        )
+
+    assert "#2563eb" in render("low", "低风险")
+    assert "#f97316" in render("medium", "中风险")
+    high_svg = render("high", "高风险")
+    assert "#dc2626" in high_svg
+    assert high_svg.count("#dc2626") == 1
+    assert "#10a37f" not in high_svg