[FEATURE] Add setting to control pasted-text placeholder collapse in the TUI composer

What feature would you like to see?

Add a user-facing setting in Codex CLI / TUI to control whether pasted text is shown inline as raw text or collapsed into a placeholder such as Pasted Content N Chars.

Right now, large pasted content is visually collapsed in the composer. That can be useful for saving space, but it removes an important workflow: reviewing the exact pasted text before submitting. For some tasks, that tradeoff is wrong. I want to be able to choose the behavior.

A few possible shapes:

• simple boolean setting, for example collapse_pasted_text = true|false
• threshold setting, for example collapse_pasted_text_threshold = 1000
• composer-level toggle or keybinding to expand/collapse pasted content before send

The key ask is configurability: let users choose placeholder mode vs raw inline text.

Additional information

This seems distinct from the existing open paste-placeholder bugs in Codex, such as:

• #11048 (Pasted text placeholder has broken behavior for longer text)
• #10387 (Large paste placeholder sent literally after $ skill selection (Tab))
• #17203 (TUI: add undo-last-paste for composer drafts)

Those are related, but this request is about product behavior and user preference, even when the placeholder implementation is working correctly.

Claude Code has an analogous feature request that’s useful as prior art and as evidence that users want to customize this UX:

• https://github.com/anthropics/claude-code/issues/23134

OpenAI’s public Codex docs currently mention disable_paste_burst, but I couldn’t find a documented setting for controlling whether pasted text is rendered as a collapsed placeholder vs raw text in the composer.