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/exec/src/event_processor_with_human_output.rs

@@ -1260,6 +1260,7 @@ fn format_collab_status(status: &AgentStatus) -> String {
     match status {
         AgentStatus::PendingInit => "pending init".to_string(),
         AgentStatus::Running => "running".to_string(),
+        AgentStatus::Interrupted => "interrupted".to_string(),
         AgentStatus::Completed(Some(message)) => {
             let preview = truncate_preview(message.trim(), 120);
             if preview.is_empty() {
@@ -1289,6 +1290,7 @@ fn style_for_agent_status(
     match status {
         AgentStatus::PendingInit | AgentStatus::Shutdown => processor.dimmed,
         AgentStatus::Running => processor.cyan,
+        AgentStatus::Interrupted => processor.yellow,
         AgentStatus::Completed(_) => processor.green,
         AgentStatus::Errored(_) | AgentStatus::NotFound => processor.red,
     }