Add the yabai internal window index to the properties

Im on OSX Monterey and wrote a status line plugin to show me the windows on the current space.
No matter how I query them, the list of windows seems to be reordered, when the focus changes.
Hence, I cannot determine the internal order that yabai uses when I switch through the windows.

Please expose said index, so I can render the windows in the correct order.

Alternatively, the result of the query is already a list, so I assumed that list to reflect yabai's internal order.

Thank you! (sorry for brevity, it has gotten quite late now :D)

Use the macOS Monterey scenario and the status-line plugin's window queries as the reproduction context. Inspect yabai's existing window properties and query response to determine where the internal window index should be exposed and how ordering currently behaves. Done means callers can retrieve the index and render windows in yabai's internal order.

Written by the indexing model from the issue text.