fix(audit): Batch 0-1 文档校准 + let _ = 静默错误修复

Batch 0:
- TRUTH.md 中间件层 14→15 (补 EvolutionMiddleware@78)
- wiki/middleware.md 同步 15 层 + 优先级分类更新
- Store 数字确认 25 个

Batch 1:
- approvals.rs: 3 处 map_err+let _ = 简化为 if let Err
- director.rs: oneshot send 失败添加 debug 日志
- task.rs: 4 处子任务状态更新添加 debug 日志
- chat.rs: 流消息发送和事件 emit 添加 warn/debug 日志
- heartbeat.rs: 告警广播添加 debug 日志 + break 优化

全量测试通过: 719 passed, 0 failed

desktop/src-tauri/src/intelligence/heartbeat.rs

@@ -383,7 +383,10 @@ async fn execute_tick(
 
     // Send alerts via broadcast channel (internal)
     for alert in &filtered_alerts {
-        let _ = alert_sender.send(alert.clone());
+        if alert_sender.send(alert.clone()).is_err() {
+            tracing::debug!("[heartbeat] No alert receivers, alert dropped");
+            break;
+        }
     }
 
     // Emit alerts to frontend via Tauri event (real-time toast)