feat(ai+health): 闭环核心 — 随访完成→再分析触发 + 前后对比报告

- follow_up.completed 消费者：通过 action_result 反查 AI 建议，触发再分析
- ai.reanalysis.requested 消费者：加载原始建议 baseline
- comparison.rs：对比报告生成引擎（指标变化百分比+趋势判断）
- GET /ai/suggestions/{id}/comparison：前后对比报告 API
- find_by_followup_task：通过随访任务反查关联建议ID

crates/erp-ai/src/module.rs

@@ -75,6 +75,54 @@ impl ErpModule for AiModule {
     fn as_any(&self) -> &dyn Any {
         self
     }
+
+    async fn on_startup(
+        &self,
+        ctx: &erp_core::module::ModuleContext,
+    ) -> erp_core::error::AppResult<()> {
+        let (mut rx, _handle) = ctx.event_bus.subscribe_filtered("ai.reanalysis.".to_string());
+        let db = ctx.db.clone();
+
+        tokio::spawn(async move {
+            loop {
+                match rx.recv().await {
+                    Some(event) if event.event_type == "ai.reanalysis.requested" => {
+                        let suggestion_id = event.payload.get("original_suggestion_id")
+                            .and_then(|v| v.as_str())
+                            .and_then(|s| uuid::Uuid::parse_str(s).ok());
+                        let patient_id = event.payload.get("patient_id")
+                            .and_then(|v| v.as_str())
+                            .and_then(|s| uuid::Uuid::parse_str(s).ok());
+
+                        match (suggestion_id, patient_id) {
+                            (Some(sid), Some(pid)) => {
+                                if let Err(e) = crate::service::reanalysis::handle_reanalysis_requested(
+                                    &db, event.tenant_id, sid, pid,
+                                ).await {
+                                    tracing::warn!(
+                                        suggestion_id = %sid,
+                                        error = %e,
+                                        "AI 再分析处理失败"
+                                    );
+                                }
+                            }
+                            _ => {
+                                tracing::warn!("ai.reanalysis.requested 事件缺少必要字段");
+                            }
+                        }
+                    }
+                    Some(_) => {}
+                    None => {
+                        tracing::info!("AI 再分析事件订阅通道已关闭");
+                        break;
+                    }
+                }
+            }
+        });
+
+        tracing::info!(module = "ai", "AI 模块事件处理器已注册（监听 reanalysis）");
+        Ok(())
+    }
 }
 
 impl AiModule {
@@ -148,5 +196,9 @@ impl AiModule {
                 "/ai/suggestions/{id}/approve",
                 axum::routing::post(crate::handler::suggestion_handler::approve_suggestion),
             )
+            .route(
+                "/ai/suggestions/{id}/comparison",
+                axum::routing::get(crate::handler::suggestion_handler::get_comparison),
+            )
     }
 }