Dock window preview

## Feature Description

Upon mouse hover on application/window icons in the dock, previews of the windows shall be shown.

## Use Case

When users have many instances of the same application open, for example a terminal or file manager, it becomes extremely hard to find the right window, as each window is currently a label that is visually identical to the other right-click menu options.

## Compositor

Is this feature specific to one compositor?

- [✅] All compositors
- [ ] niri
- [ ] Hyprland
- [ ] dwl (MangoWC)
- [ ] sway

## Proposed Solution

Remove the window labels from the application icon right-click menu, then add a horizontal window preview list that appears on hover, similar to Windows.

## Alternatives/Existing Solutions

The end-4 dotfiles have a great implementation of this in their dock! You can check it out [here](https://github.com/end-4/dots-hyprland/blob/main/dots/.config/quickshell/ii/modules/ii/dock/DockApps.qml).

Review the linked end-4 implementation in dots/.config/quickshell/ii/modules/ii/dock/DockApps.qml, then locate the corresponding dock implementation in DankMaterialShell. Done means application icons show horizontal window previews on hover and the existing window labels are removed from the right-click menu across all listed compositors.

Written by the indexing model from the issue text.