Add window layouts to the radial menu

[ruvelro]

Summary

• add Window Layout as a configurable radial-menu action type
• offer every existing placement, including Left Third, through a localized picker
• run the selected placement through WindowLayoutService after the wheel closes
• reuse the layout actions' icons in both the radial menu and the existing panel
• retain saved slices while Window Layout is unavailable, hide them until the feature returns, and request Accessibility when needed

User impact

Users can add individual placements such as “Left third”, “Maximize”, or “Next display” to any radial wheel or submenu. Selecting the slice moves the window that was active behind the non-activating wheel.

Testing

• ./build.sh --test (2950 checks)
• ./build.sh
• ./build/Vorssaint --selftest