feat: make interrupt state not final for multi-agents (#13850)

Make `interrupted` an agent state and make it not final. As a result, a
`wait` won't return on an interrupted agent and no notification will be
send to the parent agent.

The rationals are:
* If a user interrupt a sub-agent for any reason, you don't want the
parent agent to instantaneously ask the sub-agent to restart
* If a parent agent interrupt a sub-agent, no need to add a noisy
notification in the parent agen

codex-rs/app-server-protocol/src/protocol/thread_history.rs

@@ -2417,6 +2417,74 @@ mod tests {
         );
     }
 
+    #[test]
+    fn reconstructs_interrupted_send_input_as_completed_collab_call() {
+        // `send_input(interrupt=true)` first stops the child's active turn, then redirects it with
+        // new input. The transient interrupted status should remain visible in agent state, but the
+        // collab tool call itself is still a successful redirect rather than a failed operation.
+        let sender = ThreadId::try_from("00000000-0000-0000-0000-000000000001")
+            .expect("valid sender thread id");
+        let receiver = ThreadId::try_from("00000000-0000-0000-0000-000000000002")
+            .expect("valid receiver thread id");
+        let events = vec![
+            EventMsg::UserMessage(UserMessageEvent {
+                message: "redirect".into(),
+                images: None,
+                text_elements: Vec::new(),
+                local_images: Vec::new(),
+            }),
+            EventMsg::CollabAgentInteractionBegin(
+                codex_protocol::protocol::CollabAgentInteractionBeginEvent {
+                    call_id: "send-1".into(),
+                    sender_thread_id: sender,
+                    receiver_thread_id: receiver,
+                    prompt: "new task".into(),
+                },
+            ),
+            EventMsg::CollabAgentInteractionEnd(
+                codex_protocol::protocol::CollabAgentInteractionEndEvent {
+                    call_id: "send-1".into(),
+                    sender_thread_id: sender,
+                    receiver_thread_id: receiver,
+                    receiver_agent_nickname: None,
+                    receiver_agent_role: None,
+                    prompt: "new task".into(),
+                    status: AgentStatus::Interrupted,
+                },
+            ),
+        ];
+
+        let items = events
+            .into_iter()
+            .map(RolloutItem::EventMsg)
+            .collect::<Vec<_>>();
+        let turns = build_turns_from_rollout_items(&items);
+        assert_eq!(turns.len(), 1);
+        assert_eq!(turns[0].items.len(), 2);
+        assert_eq!(
+            turns[0].items[1],
+            ThreadItem::CollabAgentToolCall {
+                id: "send-1".into(),
+                tool: CollabAgentTool::SendInput,
+                status: CollabAgentToolCallStatus::Completed,
+                sender_thread_id: sender.to_string(),
+                receiver_thread_ids: vec![receiver.to_string()],
+                prompt: Some("new task".into()),
+                model: None,
+                reasoning_effort: None,
+                agents_states: [(
+                    receiver.to_string(),
+                    CollabAgentState {
+                        status: crate::protocol::v2::CollabAgentStatus::Interrupted,
+                        message: None,
+                    },
+                )]
+                .into_iter()
+                .collect(),
+            }
+        );
+    }
+
     #[test]
     fn rollback_failed_error_does_not_mark_turn_failed() {
         let events = vec![