Thoughts:
Traps of Wall of Force on all 8 sides of the cube, with holes in the wall for the firing ports.
Adapt a Ring of Force Shield to be slightly large and capable of covering the gaps in the Wall of Force.
Have a few Warforged Warlocks capable of casting Impenetrable Barrier. This way you can order "All power to forward shields". After suffering the loss of several shields due to enemy disintegration, the warlocks will take damage and engineering will have to "repair systems".
Traps of Delayed Blast Fireball for Photon Torpedos. Meteor Swarm for Quantum Torpedos. Freezing Sphere and Chain Lightening should probably be on here too. And of course, Disintegrate for... well, disintegration beams. Traps should be mounted on a mobile base in order to be aimed out the firing ports at targets.