feat: 报销审批流重构与管家计划全链路贯通

- 重构报销状态注册表、审批流路由与平台风险标记
- 完善管家意图规划器与模型计划构建器全链路
- 新增 OCR Worker 脚本、数据库会话管理与通知状态
- 优化文档中心、日志视图、预算中心与员工管理交互
- 增强工作台摘要、图标资源与全局主题样式
- 补充审批路由、状态注册、OCR 服务与管家规划器测试覆盖

server/src/app/db/session.py

@@ -18,11 +18,20 @@ def configure_session_factory() -> None:
     if _engine is not None:
         _engine.dispose()
 
-    _engine = create_engine(
-        settings.resolved_database_url,
-        echo=settings.sqlalchemy_echo,
-        pool_pre_ping=True,
-    )
+    engine_kwargs = {
+        "echo": settings.sqlalchemy_echo,
+        "pool_pre_ping": True,
+    }
+    if not settings.resolved_database_url.startswith("sqlite"):
+        engine_kwargs.update(
+            {
+                "pool_size": max(1, int(settings.sqlalchemy_pool_size or 10)),
+                "max_overflow": max(0, int(settings.sqlalchemy_max_overflow or 20)),
+                "pool_timeout": max(1, int(settings.sqlalchemy_pool_timeout or 30)),
+            }
+        )
+
+    _engine = create_engine(settings.resolved_database_url, **engine_kwargs)
     _session_factory = sessionmaker(bind=_engine, autoflush=False, autocommit=False)