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/api/v1/endpoints/analytics.py

@@ -0,0 +1,55 @@
+from __future__ import annotations
+
+from datetime import date
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, Query
+from sqlalchemy.orm import Session
+
+from app.api.deps import get_db
+from app.schemas.finance_dashboard import FinanceDashboardRead
+from app.schemas.system_dashboard import SystemDashboardRead
+from app.services.finance_dashboard import FinanceDashboardService
+from app.services.system_dashboard import SystemDashboardService
+
+router = APIRouter(prefix="/analytics")
+DbSession = Annotated[Session, Depends(get_db)]
+
+
+@router.get(
+    "/system-dashboard",
+    response_model=SystemDashboardRead,
+    summary="查询系统看板真实指标",
+    description="基于 Agent 运行、工具调用、用户会话和反馈数据聚合系统看板指标。",
+)
+def get_system_dashboard(
+    db: DbSession,
+    days: Annotated[
+        int,
+        Query(ge=1, le=30, description="统计窗口天数。"),
+    ] = 7,
+) -> SystemDashboardRead:
+    return SystemDashboardService(db).build_dashboard(days=days)
+
+
+@router.get(
+    "/finance-dashboard",
+    response_model=FinanceDashboardRead,
+    summary="查询财务看板真实指标",
+    description="基于报销单据、风险观察和预算池数据聚合财务看板指标。",
+)
+def get_finance_dashboard(
+    db: DbSession,
+    range_key: Annotated[str, Query(max_length=30, description="顶部时间范围。")] = "近10日",
+    start_date: Annotated[date | None, Query(description="自定义开始日期。")] = None,
+    end_date: Annotated[date | None, Query(description="自定义结束日期。")] = None,
+    trend_range: Annotated[str, Query(max_length=30, description="趋势图时间范围。")] = "近12天",
+    department_range: Annotated[str, Query(max_length=30, description="部门排行时间范围。")] = "本月",
+) -> FinanceDashboardRead:
+    return FinanceDashboardService(db).build_dashboard(
+        range_key=range_key,
+        start_date=start_date,
+        end_date=end_date,
+        trend_range=trend_range,
+        department_range=department_range,
+    )