feat(ai): Copilot 评分引擎 + Handler + 路由 + 权限码

- scoring.rs: 混合评分 (calculate_risk) + RiskScore/MatchedRule 结构
- engine.rs: CopilotEngine 协调规则评估和评分
- risk_service.rs: 风险计算 + UPSERT 快照 + 规则加载
- insight_service.rs: 洞察 CRUD + 过期清理
- 3 个 Handler: insight/risk/rule，7 个 API 端点
- 5 个权限码: copilot.insights.list/manage, copilot.risk.view, copilot.rules.list/manage
- AiState 扩展 risk_service + insight_service

crates/erp-server/src/main.rs

@@ -617,6 +617,8 @@ async fn main() -> anyhow::Result<()> {
             provider_registry: registry,
             quota,
             cache,
+            risk_service: std::sync::Arc::new(erp_ai::service::risk_service::RiskService),
+            insight_service: std::sync::Arc::new(erp_ai::service::insight_service::InsightService),
         }
     };