Add a way to expand collapsed [Pasted text #N +X lines] placeholders in the terminal

When pasting long text into the Claude Code CLI, it collapses to a placeholder like [Pasted text #1 +14 lines]. There's currently no way to expand or view the original pasted content from within the session — useful for verifying what was actually sent, or copying it back out.

Feature request: a keyboard shortcut or slash command (e.g. /paste show 1) to expand a given paste placeholder inline, or toggle expansion of all of them.