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/schemas/system_dashboard.py

@@ -0,0 +1,20 @@
+from __future__ import annotations
+
+from typing import Any
+
+from pydantic import BaseModel, Field
+
+
+class SystemDashboardRead(BaseModel):
+    window_days: int
+    generated_at: str
+    has_real_data: bool
+    totals: dict[str, Any] = Field(default_factory=dict)
+    agent_daily_ratio: dict[str, Any] = Field(default_factory=dict)
+    login_wave: dict[str, Any] = Field(default_factory=dict)
+    token_daily_wave: dict[str, Any] = Field(default_factory=dict)
+    user_token_usage: list[dict[str, Any]] = Field(default_factory=list)
+    accuracy_comparison: dict[str, Any] = Field(default_factory=dict)
+    usage_duration_summary: dict[str, Any] = Field(default_factory=dict)
+    feedback_summary: list[dict[str, Any]] = Field(default_factory=list)
+    tool_detail_rows: list[dict[str, Any]] = Field(default_factory=list)