feat(ai): 每日风险快照批量刷新定时任务

- risk_service 新增 refresh_all_patients 方法
- module on_startup 启动每日刷新后台任务

crates/erp-ai/src/module.rs

@@ -312,6 +312,25 @@ impl ErpModule for AiModule {
         let copilot_handles = crate::event::copilot_consumer::spawn(&ctx.db, &ctx.event_bus);
         std::mem::forget(copilot_handles);
 
+        // 每日凌晨 2:00 批量刷新所有在管患者风险快照
+        let refresh_db = ctx.db.clone();
+        tokio::spawn(async move {
+            let mut interval = tokio::time::interval(std::time::Duration::from_secs(86400));
+            loop {
+                interval.tick().await;
+                match crate::service::risk_service::RiskService::refresh_all_patients(&refresh_db)
+                    .await
+                {
+                    Ok(count) => {
+                        tracing::info!(patient_count = count, "每日风险快照刷新完成");
+                    }
+                    Err(e) => {
+                        tracing::warn!(error = %e, "每日风险快照刷新失败");
+                    }
+                }
+            }
+        });
+
         tracing::info!(
             module = "ai",
             "AI 模块事件处理器已注册（监听 ai.* 事件 + Copilot 事件）"