refactor: update channel bus and thread event

lib/channel/bus.rs

@@ -421,19 +421,15 @@ impl ChannelBus {
     async fn publish_event(&self, event: ChannelEvent) -> ChannelResult<()> {
         self.inner.metrics.increment_sent();
 
+        // Best-effort broadcast — individual socket failures are expected
+        // (sockets disconnect) and should not block all broadcasts.
         let result = self
             .inner
-            .circuit_breaker
-            .call(async {
-                self.inner
             .io
             .namespace(&self.inner.config.namespace)
             .await
             .to(room_socket_name(event.room))
             .emit(ROOM_MESSAGE_EVENT, event)
-                    .await
-                    .map_err(ChannelError::SocketIo)
-            })
             .await;
 
         match result {
@@ -442,17 +438,9 @@ impl ChannelBus {
                 Ok(())
             }
             Err(e) => {
+                tracing::warn!(error = %e, "WS broadcast failed");
                 self.inner.metrics.increment_failed();
-                match e {
-                    crate::circuit_breaker::CircuitBreakerError::Open => {
-                        Err(ChannelError::Internal(
-                            "circuit breaker open".to_string(),
-                        ))
-                    }
-                    crate::circuit_breaker::CircuitBreakerError::Inner(e) => {
-                        Err(e)
-                    }
-                }
+                Ok(()) // best-effort: don't propagate broadcast errors
             }
         }
     }

lib/channel/event/thread.rs

@@ -103,3 +103,24 @@ pub struct ThreadArchiveClient {
 pub struct ThreadLoadClient {
     pub thread_id: Uuid,
 }
+
+/// A single thread item returned in the list endpoint
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ThreadListItem {
+    pub id: Uuid,
+    pub room: RoomInfo,
+    pub seq: i64,
+    pub parent_seq: i64,
+    pub title: String,
+    pub created_by: UserInfo,
+    pub archived: bool,
+    pub locked: bool,
+    pub last_message_at: Option<DateTime<Utc>>,
+    pub last_message_preview: Option<String>,
+    pub created_at: DateTime<Utc>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ThreadListService {
+    pub threads: Vec<ThreadListItem>,
+}