fix: handle RoomUpdate variant in wzp-client signal type mapping

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/wzp-client/src/featherchat.rs

@@ -109,6 +109,7 @@ pub fn signal_to_call_type(signal: &SignalMessage) -> CallSignalType {
         SignalMessage::RouteResponse { .. } => CallSignalType::Offer, // reuse
         SignalMessage::SessionForward { .. } => CallSignalType::Offer, // reuse
         SignalMessage::SessionForwardAck { .. } => CallSignalType::Offer, // reuse
+        SignalMessage::RoomUpdate { .. } => CallSignalType::Offer, // reuse
     }
 }