fix(cable): surface tunnel connection errors via send_error

Both the QR-code and known-device channel tasks called
protocol::connection(tunnel_input).await; ux_sender.set_connection_state(Terminated).await
and discarded the result. With the previous commit propagating
post-handshake faults, route Err(e) through send_error so the
broadcast subscribers see a CableUpdate::Error before the channel
state transitions to Terminated. send_error already performs the
Terminated transition itself.

Author: AlfioEmanueleFresta

libwebauthn/src/transport/cable/known_devices.rs

@@ -223,10 +223,17 @@ impl<'d> Device<'d, Cable, CableChannel> for CableKnownDevice {
                 cbor_rx_send,
             );
 
-            protocol::connection(tunnel_input).await;
-            ux_sender
-                .set_connection_state(ConnectionState::Terminated)
-                .await;
+            match protocol::connection(tunnel_input).await {
+                Ok(()) => {
+                    ux_sender
+                        .set_connection_state(ConnectionState::Terminated)
+                        .await;
+                }
+                Err(e) => {
+                    // send_error already transitions to Terminated.
+                    ux_sender.send_error(e).await;
+                }
+            }
         });
 
         Ok(CableChannel {

libwebauthn/src/transport/cable/qr_code_device.rs

@@ -271,11 +271,17 @@ impl<'d> Device<'d, Cable, CableChannel> for CableQrCodeDevice {
                 cbor_tx_recv,
                 cbor_rx_send,
             );
-            protocol::connection(tunnel_input).await;
-
-            ux_sender
-                .set_connection_state(ConnectionState::Terminated)
-                .await;
+            match protocol::connection(tunnel_input).await {
+                Ok(()) => {
+                    ux_sender
+                        .set_connection_state(ConnectionState::Terminated)
+                        .await;
+                }
+                Err(e) => {
+                    // send_error already transitions to Terminated.
+                    ux_sender.send_error(e).await;
+                }
+            }
         });
 
         Ok(CableChannel {