Add setting to disable composer prompt suggestions

What variant of Codex are you using?

CLI

What feature would you like to see?

Please add a persistent setting to disable the suggested prompts shown in the composer.

• These suggestions are often unrelated in long-running threads and add unnecessary noise.
• This is also an accessibility issue: for screen reader users, extra suggestion content in the prompt area can increase verbosity, create navigation overhead, and make the input field less predictable.

A config option such as the following would solve this cleanly:

  [tui]
  show_prompt_suggestions = false

It would also help if disabling this removed the suggestions from both the visible
UI and the accessibility tree. Current version: codex-cli 0.114.0

Additional information

_No response_