Global search overlay doesn't account for pinned Expert drawer

## Description

When the Expert drawer (AI assistant panel) is pinned open at approximately 40% width, opening the global search (Cmd+K) results in a layout issue. The search overlay and its results dropdown don't properly account for the pinned Expert drawer, causing the UI to appear cramped and overlapping.

## Steps to Reproduce

1. Open the FlowFuse app
2. Open the Expert drawer (AI assistant panel)
3. Extend it to approximately 40% width and **pin** it
4. Press **Cmd+K** (or open the global search)

## Expected Behavior

The global search overlay should properly account for the pinned Expert drawer and render without overlapping or layout issues.

## Actual Behavior

The search dropdown and overlay don't respect the reduced viewport caused by the pinned Expert drawer, resulting in a cramped and overlapping UI.

## Screenshot