Best option for preventing labels from touching edge of map

Hello!

I am trying to prevent map labels from getting placed such that they get cut off from the edge of the map for my project (IRLMap.com). In the screenshot below, I show examples of labels that are getting cut off marked with 🚫.

My first idea was to create a rectangular polygon at the perimeter of my map, but doing so did not appear to shift the underlying labels. My second idea comes from the insight that I notice my points DO shift underlying labels out of the way: add a series of invisible points at the perimeter of the map, but this feels hacky and strange.

What is the best approach for preventing labels from touching the edge of my map?

Start by reproducing the label-placement examples shown in the linked screenshot and compare the behavior of perimeter polygons with invisible perimeter points. Done should be a documented, supported approach for preventing labels from being clipped at the map edge, with the result reflected in the issue or an accompanying test.