macOS desktop audio recording stops when switching threads

Summary

On the macOS desktop app, switching threads while audio recording / dictation is active stops the recording and cuts off the current audio capture.

Repro

1. Open Codex on macOS desktop.
2. Start recording audio / dictation in the current thread composer.
3. While recording is still active, click a different thread in the sidebar.

Observed

The audio recording is cut off immediately when the thread changes. The in-progress recording does not continue, and the captured input can be lost/interrupted.

Expected

Switching threads should not silently discard or cut off an active recording. Reasonable behaviors would include one of:

• keep recording active while the selected thread changes,
• preserve the recording with the original thread until it is submitted/cancelled,
• or warn before switching if the recording must be stopped.