diag(tunnel): writer/reader 帧计数诊断日志

- writer task 记录发送帧数、Binary 帧大小、send 失败原因
- reader 记录接收帧总数，disconnect 时输出
- 用于定位 gateway→proxy 数据流是否正常

apps/aether-gateway/src/tunnel/embedded/proxy_conn.rs

@@ -41,14 +41,36 @@ pub async fn handle_proxy_connection(
 
     hub.register_proxy(conn.clone());
 
+    let writer_conn_id = conn_id;
     let writer = tokio::spawn(async move {
+        let mut frames_sent: u64 = 0;
         loop {
             tokio::select! {
                 msg = rx.recv() => match msg {
                     Some(msg) => {
-                        if ws_tx.send(msg).await.is_err() {
+                        let is_binary = matches!(&msg, Message::Binary(_));
+                        let msg_len = match &msg {
+                            Message::Binary(b) => b.len(),
+                            _ => 0,
+                        };
+                        if let Err(e) = ws_tx.send(msg).await {
+                            warn!(
+                                conn_id = writer_conn_id,
+                                frames_sent = frames_sent,
+                                error = %e,
+                                "writer ws_tx.send failed"
+                            );
                             break;
                         }
+                        frames_sent += 1;
+                        if is_binary && msg_len > protocol::HEADER_SIZE {
+                            debug!(
+                                conn_id = writer_conn_id,
+                                size = msg_len,
+                                frames_sent = frames_sent,
+                                "writer sent binary frame"
+                            );
+                        }
                     }
                     None => break,
                 },
@@ -59,6 +81,11 @@ pub async fn handle_proxy_connection(
                 }
             }
         }
+        info!(
+            conn_id = writer_conn_id,
+            frames_sent = frames_sent,
+            "writer task exiting"
+        );
         let _ = ws_tx.close().await;
     });
 
@@ -99,11 +126,13 @@ async fn run_proxy_reader(
     conn: Arc<ProxyConn>,
 ) {
     let mut oversized_count = 0u32;
+    let mut frames_received: u64 = 0;
     loop {
         let msg = ws_rx.next().await;
 
         match msg {
             Some(Ok(Message::Binary(data))) => {
+                frames_received += 1;
                 let mut data = data.to_vec();
                 if data.len() > MAX_FRAME_SIZE {
                     oversized_count += 1;
@@ -129,11 +158,21 @@ async fn run_proxy_reader(
                 hub.handle_proxy_frame(conn.id, &mut data).await;
             }
             Some(Ok(Message::Close(_))) | None => {
-                info!(conn_id = conn.id, node_id = %conn.node_id, "proxy WebSocket closed");
+                info!(
+                    conn_id = conn.id,
+                    node_id = %conn.node_id,
+                    frames_received = frames_received,
+                    "proxy WebSocket closed"
+                );
                 break;
             }
             Some(Err(e)) => {
-                warn!(conn_id = conn.id, error = %e, "proxy WebSocket error");
+                warn!(
+                    conn_id = conn.id,
+                    frames_received = frames_received,
+                    error = %e,
+                    "proxy WebSocket error"
+                );
                 break;
             }
             Some(Ok(Message::Ping(payload))) => {