fix: 添加 WebSocket 重连成功日志，优化重连逻辑

frontend/src/file-manager.ts

@@ -272,6 +272,11 @@ export class FileManager {
 
     socket.addEventListener('open', () => {
       if (!this.isCurrent(socket, generation)) return;
+      if (this.reconnectAttempts > 0) {
+        console.log(
+          `[WS-Reconnect] ${new Date().toISOString()} | SFTP | reconnect_success | attempt=${this.reconnectAttempts}/${RECONNECT_MAX_ATTEMPTS}`,
+        );
+      }
       this.reconnectAttempts = 0;
       this.init();
     });

frontend/src/process-manager.ts

@@ -293,6 +293,11 @@ export class ProcessManager {
     this.setStatus('正在启动进程监控…', 'Starting process monitor…');
     socket.addEventListener('open', () => {
       if (!this.isCurrent(socket, generation)) return;
+      if (this.reconnectAttempts > 0) {
+        console.log(
+          `[WS-Reconnect] ${new Date().toISOString()} | Process | reconnect_success | attempt=${this.reconnectAttempts}/${RECONNECT_MAX_ATTEMPTS}`,
+        );
+      }
       this.reconnectAttempts = 0;
       socket.send(JSON.stringify({ type: 'process_start' }));
     });

frontend/src/ws-reconnect.ts

@@ -106,6 +106,11 @@ export class WebSocketReconnectManager {
 
   private handleClose(event: CloseEvent): void {
     if (this.destroyed) return;
+    // Guard: ignore close events from superseded sockets that have been
+    // replaced by a newer attach() or a successful reconnect.  Without
+    // this check a stale socket closing later could trigger a spurious
+    // reconnection cycle.
+    if (event.target !== this.socket) return;
 
     this.log({
       timestamp: new Date().toISOString(),