[Desktop App / Windows] Dragging panel headers moves entire app window instead of panels

Description

On the Windows desktop app, dragging panel headers (Tasks, Plan, Terminal, etc.) moves the entire application window instead of repositioning the panel within the app layout. On macOS, panels can reportedly be dragged and rearranged as expected.

Steps to Reproduce

1. Open Claude Code Desktop App on Windows
2. Open any panel (Tasks, Plan, Terminal, etc.)
3. Try to drag the panel by its header to reposition it

Expected Behavior

The panel should be repositioned/rearranged within the app layout (as it works on macOS).

Actual Behavior

The entire application window moves, as if dragging the app's title bar. The panel itself does not move or reposition within the layout.

Environment

• OS: Windows 11 Pro 10.0.26200
• App: Claude Code Desktop App (latest)

Notes

This appears to be a platform-specific issue where the panel header drag event is being captured by the window's drag handler (likely an Electron --webkit-app-region: drag conflict) instead of the panel layout system.