Run button on shell code blocks in chat

[GabrieleCurti]

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the request.

Area

apps/web

Problem or use case

Copy is the only action on a code block right now. When the agent tells you to run something, you copy it, open the terminal drawer, click in, paste, hit enter. Every single time.

Expected behavior

A run button next to copy on shell code blocks in chat. Click it, it opens (or reuses) the thread's terminal at the project cwd and writes the command, same as clicking a saved project script.

Smallest useful scope

Web only. Add the button to the existing MarkdownCodeBlock toolbar (it already has copy and wrap), thread a callback through ChatMarkdownRendererContext, reuse runProjectScript (ChatView.tsx) for the actual terminal open/write. Restrict to shell-language fences for the first pass, not multi-line scripts or non-shell languages.

Someone already tried this in #472, closed without merging, no comment on why. It's six months stale now, ChatMarkdown.tsx changed shape since (the toolbar didn't exist back then), so a new attempt wouldn't reuse much of that diff.

Mobile renders code blocks through a separate native module that only has copy today, no shared code with web's markdown pipeline. Worth doing later, not blocking this.

Why this matters

Agents propose a shell command in basically every session that touches setup, tests, migrations, or git. It's one of the most repeated actions in the whole product, and right now it's copy, switch tabs, paste, enter, every time. On mobile it's worse: switching tabs and tapping into a PTY input on a phone keyboard. Copy-paste also has a real failure mode, retyping or pasting into the wrong terminal or cwd. A button removes basically all of that for the single most common "close the loop" step in a session.

Contribution

• I would be open to helping implement this.

For more context

#472