Add per-response copy button on Android

[ltz6]

Hi Daniel,

Thank you again for continuing to improve Litter.

I would like to request a small but useful feature on Android: add a copy button for each assistant response, similar to a per-message or per-section "copy response" action.

Current issue:

• On Android, it is difficult to select and copy an entire assistant response directly.
• This becomes especially problematic when the response contains code blocks, Markdown, or mixed text and code.
• Touch selection often breaks around code output, so the relevant part cannot be copied continuously.

Requested behavior:

• Add a copy action for each assistant response or response section.
• The action should copy the full text of that response, including code blocks and Markdown formatting.
• If possible, also support copying individual code blocks separately.

This would make Litter much easier to use on Android when reviewing or reusing generated code, commands, Markdown, or technical explanations.

Thanks.