Support steering active Codex turns from queued messages

[Liu-KM]

Summary

Add support for steering an active Codex app-server turn with queued messages.

• add typed turn/steer support to the Codex app-server client
• when a same-mode message arrives while a turn is active, send it to turn/steer
• requeue messages if steering fails
• keep turn lifecycle state active until a terminal turn event arrives, preventing a second turn from starting too early

Why

Codex can accept additional instructions while a task is running. HAPI previously queued those messages for a later turn, and could also start another turn before the active turn had emitted a terminal event, which could leave sessions stuck in a thinking state.

Validation

• cd cli && bun x vitest run src/codex/codexRemoteLauncher.test.ts

Notes

AI-assisted with GPT-5.4.

[github-actions]

Findings

• [Major] Messages queued before the turn id is known are not re-checked for steering, so they can fall through to the next turn. Evidence cli/src/codex/codexRemoteLauncher.ts:261, cli/src/codex/codexRemoteLauncher.ts:771.
  Suggested fix:

  if (turnId) {
      this.currentTurnId = turnId;
      void maybeSteerQueuedMessages();
  }

• [Major] await turnSettled can hang indefinitely if the app-server exits after turn/start succeeds but before a terminal event arrives. Evidence cli/src/codex/codexRemoteLauncher.ts:762, cli/src/codex/codexRemoteLauncher.ts:776, context cli/src/codex/codexAppServerClient.ts:99.
  Suggested fix:

  appServerClient.setDisconnectHandler(() => {
      turnInFlight = false;
      activeTurnModeHash = null;
      this.currentTurnId = null;
      settleTurnInFlight();
  });

Summary
Review mode: initial
The new steering path still misses one active-turn window and can deadlock the remote launcher on app-server disconnect. Residual testing gap: not found coverage for messages queued before turn_id becomes available or for disconnects after turn/start.

Testing
Not run (automation; static review only per prompt constraints)

HAPI Bot

[github-actions]

[MAJOR] This early return means a same-mode message that lands after turnInFlight = true but before currentTurnId is populated will miss the steering window. setOnMessage() fires once, exits here, and nothing re-runs maybeSteerQueuedMessages() when startTurn() or turn/started later provides the turn id, so that message waits for a later turn instead of steering the active one.

Suggested fix:

if (turnId) {
    this.currentTurnId = turnId;
    void maybeSteerQueuedMessages();
}

[github-actions]

[MAJOR] turnSettled is only resolved from terminal notifications. If the app-server exits after turn/start returns but before turn/completed, CodexAppServerClient only rejects pending RPCs (cli/src/codex/codexAppServerClient.ts:99), so this await never resolves and the session stays stuck in thinking while cleanup never runs.

Suggested fix:

appServerClient.setDisconnectHandler(() => {
    turnInFlight = false;
    activeTurnModeHash = null;
    this.currentTurnId = null;
    settleTurnInFlight();
});