Remove TUI realtime voice support

[etraut-openai]

Why

Removes the realtime audio support from TUI.

What Changed

• Removed the TUI /realtime and realtime /settings command paths.
• Deleted TUI voice capture/playback, WebRTC session handling, audio-device selection UI, and recording-meter code.
• Removed TUI realtime tests and snapshots that covered the deleted surfaces.
• Dropped the TUI-only cpal and codex-realtime-webrtc dependencies and refreshed the Rust/Bazel locks.

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 3731b0fad7

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".