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/src/app/services/agent_foundation.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+import threading
+
 from sqlalchemy import select
 from sqlalchemy.orm import Session
 
@@ -31,6 +33,8 @@ from app.services.agent_foundation_risk_rules import AgentFoundationRiskRuleMixi
 from app.services.agent_foundation_spreadsheets import AgentFoundationSpreadsheetMixin
 
 logger = get_logger("app.services.agent_foundation")
+_foundation_ready_lock = threading.RLock()
+_foundation_ready_keys: set[str] = set()
 
 
 def prepare_agent_foundation() -> None:
@@ -57,6 +61,17 @@ class AgentFoundationService(
         self.db = db
 
     def ensure_foundation_ready(self) -> None:
+        cache_key = self._foundation_cache_key()
+        if cache_key in _foundation_ready_keys:
+            return
+
+        with _foundation_ready_lock:
+            if cache_key in _foundation_ready_keys:
+                return
+            self._prepare_foundation()
+            _foundation_ready_keys.add(cache_key)
+
+    def _prepare_foundation(self) -> None:
         try:
             Base.metadata.create_all(bind=self.db.get_bind())
             self._ensure_agent_asset_schema()
@@ -69,6 +84,10 @@ class AgentFoundationService(
             logger.exception("Failed to prepare agent foundation")
             raise
 
+    def _foundation_cache_key(self) -> str:
+        bind = self.db.get_bind()
+        return str(getattr(bind, "url", "") or id(bind))
+
     def _sync_demo_financial_records(self) -> None:
         if get_settings().seed_demo_financial_records:
             self._seed_financial_records()