Add 'Focus/Toggle Input' action to toggle the panel when it is already focused

[oxysoft]

Toggle / hide the Kilo Code panel or sidebar when the action is fired with the textbox already focused. This will allow users to use it more like Cursor. Personally I'm not sure that the pure focus-only action is all that useful, but in case somebody is used to and likes this UX quirk I reckon we should add a new action.