fix(cable): return ConnectionFailed for both Terminated paths

wait_for_connection returned ConnectionLost when the channel was already
Terminated on entry, but ConnectionFailed when it became Terminated during
the changed() await. The caller can't observe which path it took, so the
two variants are an accidental asymmetry that makes downstream matches
fragile. Both paths now return ConnectionFailed.

Author: AlfioEmanueleFresta

libwebauthn/src/transport/cable/channel.rs

@@ -55,9 +55,13 @@ impl CableChannel {
             return Ok(());
         }
 
-        // If already terminated, return error immediately
+        // If already terminated, return error immediately. Mirror the
+        // post-`changed()` branch below so that an early-terminated channel
+        // surfaces the same variant as one that terminates while we wait;
+        // the caller can't observe the timing difference and the asymmetry
+        // was accidental.
         if *rx.borrow() == ConnectionState::Terminated {
-            return Err(Error::Transport(TransportError::ConnectionLost));
+            return Err(Error::Transport(TransportError::ConnectionFailed));
         }
 
         // Wait for state change