Shellworld

Shell megastructure built around an otherwise - uninhabitable world. It can hold an atmosphere inside it and heat up or cool the surface. It also protects against orbital bombardment, and anti starship weaponry can be mounted to the outtside of the shell. If the shell is penetrated, it should be repaired quickly or the planet will lose its atmosphere. Factions that do not have teleportation technology require specially designed vacuum sealed space elevators are used to get in and out.
This heating/cooling process is often performed using QEN heat vents. To heat a world up, some of the heat is directed into the planet but to keep it from becoming too hot, some radiation is also radiated into space using similar heat vents. Before the construction of the first shellworld ever built, Medora, it was necessary to build large domes on a world to make parts of the world habitable. This was resource intensive and only allowed the Hyperion Federation to inhabit sections of the world in question.
Shellworlds would allow the entire world to be inhabited, as well as install a new atmosphere on the world, so it can replicate any desired conditions regardless of the size/temperature/makeup of the world in question. Graviton Wave Refraction can be used to increase or reduce the total gravity of the world.
Another key advantage of shellworlds is that it makes the world in question more difficult to invade. The world would be rendered uninhabitable should the shell be penetrated, but this is very rarely done even by genocidal factions, as the population living on the worlds is valuable. (regular planets arent destroyed for a similar reason). Shellworlds can have a large amount of weapons installed on the exterior if needed, and can become very powerful fortresses. Some can jam Teleporters as well, so invading factions would have to introduce some new method of invasion that is not teleportation.
Shellworlds have been subject to controversy however. If an asteroid was to collide with the shellworld, this would create a hole. Although this is less of a concern because there are various large weapons mounted to the exterior, many are still scared of the possibility.