Codex Desktop: add a read-aloud / replay audio button for assistant responses

Feature request

Add a read aloud / replay audio button to assistant responses in the Codex desktop app, similar to the speaker/replay behavior available on chatgpt.com.

Why

Codex Desktop is increasingly used for long-running, conversational coding work. Being able to replay an assistant response as voice would make the desktop app easier to use while multitasking, reviewing long explanations, or working in a hands-busy flow.

This would also improve accessibility and parity with ChatGPT's web UI.

Proposed UX

For each assistant response in Codex Desktop:

• Show a small speaker/play button in the response action row.
• Clicking it reads the response aloud.
• While playing, show pause/stop/replay state.
• The action should work on already-completed responses, not only during streaming.
• Ideally, preserve the same behavior/style as chatgpt.com so users do not have to learn a new control.

Nice-to-have behavior

• Respect the user's ChatGPT/Codex voice settings if available.
• Provide a simple fallback OS TTS voice if cloud voice playback is unavailable.
• Avoid reading hidden metadata, tool JSON, or internal reasoning; read only the visible assistant answer unless the user explicitly expands/selects another item.
• If a response contains code blocks, either skip them by default or use a readable summary mode.

Context

The desktop app already has rich response actions and long-form coding conversations. Voice replay would be a small but high-leverage quality-of-life feature, especially for users who keep Codex open as an active desktop companion while coding.