Codex TUI should support image paste via Cmd-V / terminal paste, not only Ctrl-V

What variant of Codex are you using?

CLI

What feature would you like to see?

Useful body:

## Environment

• Codex: codex-cli 0.133.0
• OS: macOS
• Terminal: iTerm2
• Clipboard contents: screenshot/image

## Current behavior

In Codex TUI, image paste works with Ctrl-V, but Cmd-V does not paste/attach the image. This is confusing on macOS because
Cmd-V is the normal paste gesture and works for text paste.

## Expected behavior

Codex should make image paste discoverable and ergonomic on macOS, ideally by handling Cmd-V/terminal paste where possible, or
showing a hint when the clipboard contains an image and Cmd-V cannot attach it.

## Why this matters

Claude Code appears to handle this path more ergonomically, while Codex requires knowing that Ctrl-V is the image paste
shortcut.

I’d tag it as an enhancement / CLI / TUI / macOS issue if the chooser lets you.

Additional information

_No response_