Issue: Moving to a display with an empty space - could not locate a window below the cursor

## Summary
Thanks for making Yabai, its an awesome application!

My issue is the following:
`yabai -m display --focus ` fails with `could not locate a window below the cursor.` when the target display/space has no windows (empty space). This makes it hard to reliably focus displays in scripts on a multi-monitor setup.

## Environment
- macOS: Tahoe 26.2
- yabai: v7.1.16
- SIP: disabled
- yabai mode: Scripting additions enabled
- Displays: 3 monitors
- Spaces: 3 spaces per display.
- Mission Control settings:
- Displays have separate Spaces: on
- mouse_follows_focus: Enabled

## What I’m trying to do
To illustrate the issue I simply run a terminal command to focus a specific display when the currently-visible space on that display is empty:
```sh
> yabai -m display --focus 2
could not locate a window below the cursor.
```
Any suggestions are appreciated.

Start by reproducing `yabai -m display --focus 2` with three monitors and an empty target space under macOS Tahoe 26.2, with mouse_follows_focus enabled and scripting additions enabled. Investigate how display focus handles an empty space; done means focusing the requested display succeeds without the `could not locate a window below the cursor` error.

Written by the indexing model from the issue text.