CmdPal: Dock - keyboard shortcut to focus the Dock

### Description of the new feature / enhancement

Add a global keyboard shortcut that would activate the Dock (e.g. first band), so the user can them use common keyboard navigation to work with the dock.

### Scenario when this would be used?

UX for keyboard positive humans

### Supporting information

_No response_

The issue names CmdPal's Dock and its first band but no files or tests. Start by locating Dock focus handling and global shortcut registration, then confirm the intended shortcut and navigation behavior with maintainers. Done means a global shortcut activates the Dock and keyboard navigation continues from the first band.

Written by the indexing model from the issue text.