feat(v0.8.44): steer instead of queue when busy-waiting (#2009)

When the model is busy but not actively streaming text (waiting on
tool results, sub-agents, or shell commands), Enter now tries to steer
the message into the current turn rather than silently queueing it.
If steering fails, the message falls back to queuing.

During active streaming, Enter still queues to avoid interrupting
in-flight reasoning. Ctrl+Enter forces Steer in all busy states.

crates/tui/src/tui/app.rs

@@ -4282,13 +4282,17 @@ impl App {
 
     /// Decide how to route a fresh composer submit.
     ///
-    /// #382: default to Queue when busy — the user shouldn't have to distinguish
-    /// "streaming" from "tool execution". Ctrl+Enter overrides to Steer.
+    /// #382 / v0.8.44: when the model is busy but not actively streaming
+    /// (waiting on tool results, sub-agents, or shell commands), Enter tries
+    /// to steer into the current turn. If steering fails, the message queues.
+    /// During active streaming, Enter always queues to avoid interrupting
+    /// in-flight reasoning. Ctrl+Enter forces Steer in all busy states.
     ///
     /// Truth table:
-    ///   offline=F, busy=F → Immediate
-    ///   offline=F, busy=T → Queue  (was Steer for non-streaming; now unified)
-    ///   offline=T, busy=* → Queue
+    ///   offline=F, busy=F           → Immediate
+    ///   offline=F, busy=T+streaming → Queue
+    ///   offline=F, busy=T+waiting   → Steer (fallback Queue)
+    ///   offline=T, busy=*           → Queue
     #[must_use]
     pub fn decide_submit_disposition(&self) -> SubmitDisposition {
         if self.offline_mode {
@@ -4297,7 +4301,13 @@ impl App {
         if !self.is_loading {
             return SubmitDisposition::Immediate;
         }
-        // Busy: always queue. Ctrl+Enter routes through steer_user_message directly.
+        // Busy but not streaming text: model is waiting on tool results or
+        // sub-agents — steer so the new message reaches the engine promptly
+        // instead of sitting in the queue until the current turn finishes.
+        if self.streaming_message_index.is_none() {
+            return SubmitDisposition::Steer;
+        }
+        // Actively streaming: queue to avoid interrupting in-flight reasoning.
         SubmitDisposition::Queue
     }
 
@@ -6300,13 +6310,14 @@ mod tests {
     }
 
     #[test]
-    fn submit_disposition_queue_when_busy_and_online_not_streaming() {
-        // #382: Busy + not streaming → Queue (was Steer; now unified)
+    fn submit_disposition_steer_when_busy_and_online_not_streaming() {
+        // v0.8.44: Busy + not streaming → Steer (Enter reaches engine during
+        // sub-agent/shell waits instead of silently queueing).
         let mut app = App::new(test_options(false), &Config::default());
         app.is_loading = true;
         app.offline_mode = false;
         // streaming_message_index is None (default) → tool execution phase
-        assert_eq!(app.decide_submit_disposition(), SubmitDisposition::Queue);
+        assert_eq!(app.decide_submit_disposition(), SubmitDisposition::Steer);
     }
 
     #[test]

crates/tui/src/tui/ui.rs

@@ -5339,7 +5339,8 @@ async fn submit_or_steer_message(
             }
             Ok(())
         }
-        // Steer and QueueFollowUp are now only reached via Ctrl+Enter override.
+        // Steer: reached via Enter when busy-but-waiting (v0.8.44), or
+        // via Ctrl+Enter override in any busy state.
         SubmitDisposition::Steer => {
             if let Err(err) = steer_user_message(app, engine_handle, message.clone()).await {
                 app.queue_message(message);