Preview panel has no visual indicator that it's a preview

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

The Preview panel (right side) has no header, label, or icon indicating it's a preview. It only shows the filename in the tab (e.g. "privacy-choices.html"), making it indistinguishable from an editor tab or built-in panel.

This is confusing when a preview server from a previous session is still visible — there's no context for why it's there or what it is.

Proposed Solution

Add a clear "Preview" label/header to the panel, similar to how "Terminal" and "Output" panels are labeled.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

Interactive mode (TUI)

Use Case Example

I told Claude "the preview panel with Privacy Choices is appearing on the right" and Claude couldn't understand what I meant — it asked me to clarify whether I meant an Xcode preview, an in-app screen, or a website. Because the Preview panel has no visible label or header, I had no way to describe it clearly. A simple "Preview" label would have let me say "the Preview panel" and be immediately understood.

Additional Context

<img width="1909" height="919" alt="Image" src="https://github.com/user-attachments/assets/e0742ed3-f0b4-4824-8823-64dfe4288df1" />