[Feature request] window_placement depending on where window is coming from

Hi folks,
thanks for this amazing tool.
I have a feature request for you.
In a multi-monitor (3) setup I am moving windows with these commands eg. to the right:

```bash
yabai -m window --swap east || $(yabai -m window --display east; yabai -m display --focus east)
```

However, if I move a window from my centre monitor to the right one and the right monitor already has a window the moved window will appear on the right side instead of the left. I guess this is due to the window_placement second_child property.

This feels very unnatural, especially because coming from the other side it works as expected.

Reproduce the three-monitor scenario using the supplied yabai window and display commands, comparing moves from each direction. Start by tracing the window_placement behavior around its second_child property; done means a window moved onto an occupied monitor is placed consistently on the expected side regardless of its source monitor.

Written by the indexing model from the issue text.