feat: 新增风险图谱算法与系统仪表盘及操作反馈体系

后端新增风险图谱算法模块、风险观察与反馈服务、规则 DSL
校验器和可解释性引擎，完善系统仪表盘和财务仪表盘统计，
优化 agent 运行和编排执行链路，清理旧开发文档，前端新增
系统趋势、负载热力图等多种仪表盘图表组件，完善操作反馈
对话框和工作台日期选择器，优化报销创建和审批详情交互，
补充单元测试覆盖。

server/src/app/services/auth.py

@@ -16,6 +16,7 @@ from app.schemas.auth import AuthUserRead, LoginRequest, LoginResponse
 from app.services.employee import EmployeeService
 from app.services.employee_seed import ROLE_DISPLAY_ORDER
 from app.services.settings import SettingsService
+from app.services.user_session_metrics import UserSessionMetricService
 
 logger = get_logger("app.services.auth")
 
@@ -62,7 +63,7 @@ class AuthService:
         admin_user = self._authenticate_admin(identifier, password)
         if admin_user is not None:
             logger.info("Admin login succeeded identifier=%s", identifier)
-            return LoginResponse(user=self._serialize_user(admin_user))
+            return self._build_login_response(admin_user)
 
         employee_user = self._authenticate_employee(identifier, password)
         if employee_user is not None:
@@ -71,11 +72,15 @@ class AuthService:
                 identifier,
                 ",".join(employee_user.role_codes),
             )
-            return LoginResponse(user=self._serialize_user(employee_user))
+            return self._build_login_response(employee_user)
 
         logger.warning("Login failed identifier=%s", identifier)
         raise ValueError("账号或密码错误。")
 
+    def _build_login_response(self, user: AuthenticatedUser) -> LoginResponse:
+        session = UserSessionMetricService(self.db).start_session(user)
+        return LoginResponse(user=self._serialize_user(user), sessionId=session.session_id)
+
     def _authenticate_admin(self, identifier: str, password: str) -> AuthenticatedUser | None:
         record = SettingsService(self.db).verify_admin_login(identifier, password)
         if record is None: