JDC start_downstream_server breaks loop on fallback

miner-apps/jd-client/src/lib/channel_manager/mod.rs

@@ -476,13 +476,21 @@ impl ChannelManager {
         })?;
 
         let task_manager_clone = task_manager.clone();
+        // Register the listener task in fallback coordination, so fallback waits
+        // for this accept loop to stop before attempting to re-bind the same port.
+        let fallback_handler = fallback_coordinator.register();
+        let fallback_token = fallback_coordinator.token();
         task_manager.spawn(async move {
             loop {
                 select! {
                     _ = cancellation_token.cancelled() => {
                         info!("Downstream Server: received shutdown signal");
                         break;
                     }
+                    _ = fallback_token.cancelled() => {
+                        info!("Downstream Server: received fallback signal");
+                        break;
+                    }
                     res = server.accept() => {
                         match res {
                             Ok((stream, socket_address)) => {
@@ -568,6 +576,7 @@ impl ChannelManager {
                 }
             }
             info!("Downstream server: Unified loop break");
+            fallback_handler.done();
         });
         Ok(())
     }