feat: save event_loop handle to avoid ghost session

src/connection.rs

@@ -98,6 +98,7 @@ pub struct ConnectionStatus {
     pub poll_points: Arc<Vec<PollPointInfo>>, // 正在轮询的点集合
     poll_handle: Option<JoinHandle<()>>, // 统一的轮询任务句柄
     heartbeat_handle: Option<JoinHandle<()>>, // 心跳任务句柄
+    event_loop_handle: Option<JoinHandle<opcua::types::StatusCode>>, // event_loop 任务句柄
 }
 
 #[derive(Clone)]
@@ -577,8 +578,13 @@ impl ConnectionManager {
             }
         };
 
-        let _ = event_loop.spawn();
-        session.wait_for_connection().await;
+        let event_loop_handle = event_loop.spawn();
+        
+        if !session.wait_for_connection().await {
+            let error = "Session connection failed".to_string();
+            self.fail_connect(source_id, &error).await;
+            return Err(error);
+        }
 
         let mut status = self.status.write().await;
         status.insert(
@@ -595,6 +601,7 @@ impl ConnectionManager {
                 poll_points: Arc::new(Vec::new()),
                 poll_handle: None,
                 heartbeat_handle: None,
+                event_loop_handle: Some(event_loop_handle),
             },
         );
         drop(status); // 显式释放锁，在调用 start_unified_poll_task 之前
@@ -625,6 +632,7 @@ impl ConnectionManager {
                 poll_points: Arc::new(Vec::new()),
                 poll_handle: None,
                 heartbeat_handle: None,
+                event_loop_handle: None,
             },
         );
     }
@@ -661,6 +669,10 @@ impl ConnectionManager {
                 if let Some(handle) = conn_status.heartbeat_handle.take() {
                     handle.abort();
                 }
+                // 停止 event_loop 任务
+                if let Some(handle) = conn_status.event_loop_handle.take() {
+                    handle.abort();
+                }
             }
         }
 
@@ -693,6 +705,10 @@ impl ConnectionManager {
                     if let Some(handle) = conn_status.heartbeat_handle.take() {
                         handle.abort();
                     }
+                    // 停止 event_loop 任务
+                    if let Some(handle) = conn_status.event_loop_handle.take() {
+                        handle.abort();
+                    }
                 }
             }