Pasted text containing $ gets corrupted when expanding [Pasted ~N lines] placeholders #33699

Description

Pasting text into the TUI prompt collapses it into a [Pasted ~N lines] placeholder, with the real text stored on the prompt part. When that placeholder is expanded back to the full text, the pasted text is passed as the replacement string to String.prototype.replace. A string replacement interprets $ sequences ($$, $&, $`, $'), so pasted code that contains them comes back altered.

Two flows are affected: copying the prompt back to the clipboard, and opening the prompt in the external editor. The submit path is fine because it uses the range-based expander.

Examples (pasted text on the left, what you get back on the right):

• const x = ${a}$$ becomes const x = ${a}$ (the $$ collapses to one $)
• echo $&done becomes echo [Pasted ~N lines]done ($& re-inserts the placeholder string into the code)
• $` and $' are mangled the same way (they pull in text from around the placeholder)

OpenCode version

dev (1.17.9)

Steps to reproduce

1. Paste a multi-line block containing $$ or $& (shell or template-literal code, for example) into the prompt so it collapses to [Pasted ~N lines].
2. Copy the prompt to the clipboard, or open it in the external editor.
3. The text you get back differs from what you pasted.