Opening a session that needs input from a fullscreen Browser preview does not show chat

## Steps to reproduce

1. In the Agents window, use the single-pane detail panel layout.
2. Open a Browser preview in the single detail pane and maximize it to full screen.
3. From the title bar, open a different session when it's blinking the 'needs input' banner.

## Actual behavior

The single detail panel switches to the selected session, but the chat for that session is not shown. As a result, the input request that needs attention remains hidden.

## Expected behavior

Opening a session that needs input should reveal and focus the chat for that session, including the input request, even when the previous session was showing a fullscreen Browser preview.