Use Window color roles for app drawer and overlay scrims, and update\ndock keyboard navigation focus paths. Extend folio and convergence\nregression checks to lock in the new theme and navigation behavior.
In convergence mode the app drawer appears as a sized popup
anchored above the dock near the Overview button, instead of
taking over the full screen.
- Popup has rounded background, shadow, and clipped content
- Desktop stays visible behind the popup (no scale/fade/blur)
- Click outside the popup dismisses it
- Wallpaper scrim suppressed in convergence mode
- Mobile behavior is unchanged
