no hand holding

The line under every nav row, the line under every font select, and the caption
under the preview. Each explained a control to somebody who has already found
it, and the caption was wrong as well — there is no Save to press.

The nav rows are one line now, so they centre.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

web/SitePreview.tsx

@@ -352,11 +352,6 @@ export const SitePreview = ({
         </div>
       </div>
 
-      {/* Always, now that editing is the only mode. It says which server this is and at what width,
-          which the device buttons show but the SERVER half of it — dev, not production — they do not. */}
-      <p className="shrink-0 text-[10px] text-muted-foreground">
-        The development server, live at {frameWidth}px. Save to see a change here.
-      </p>
     </section>
   );
 };