Feature request: add spell-check to the CLI prompt editor

What feature would you like?

Add built-in spell-check support to the Codex CLI prompt editor. Misspelled words should be identified while typing, with an accessible way to view and apply correction suggestions.

Suggested behavior:

• Underline or otherwise mark likely misspellings.
• Offer correction suggestions through a keyboard-accessible menu or shortcut.
• Respect the user's configured language/dictionary.
• Provide a setting to enable or disable spell-check.

Why is this useful?

Prompts often contain detailed natural-language instructions, so catching typing mistakes before submission improves clarity and reduces avoidable misunderstandings. Claude Code CLI already provides spell-check, and equivalent support would improve the Codex CLI writing experience.

The existing Ctrl+G external-editor workflow is useful for long prompts, but it adds friction for ordinary messages and is not a replacement for inline checking.

Environment

• Codex CLI: 0.155.0
• OS: Linux (Arch Linux, x86_64)

Start by locating the CLI prompt editor and the existing Ctrl+G external-editor workflow. Compare the requested behavior with spell-check support in Claude Code CLI, then trace how prompt input, keyboard shortcuts, settings, and language preferences are handled. Done means misspellings are marked while typing, suggestions are keyboard-accessible, the configured dictionary is respected, and spell-check can be toggled.