I don't see the necessity. I have commuted on suspension forks and am a clyde but the forks have all been stiff enough that they stayed at the top of their travel during normal pedaling, though they did bob when I had to stand up to climb hills.

Plus, if it's five miles, get a full suspension mtb. That's not too far. The only hurdle is the difficulty of mounting racks or fenders. I commuted 11.1 miles one way on a rather soft full suspension bike. You'll learn to pedal in circles instead of mash, but it's still only five miles.

Your MTB handling skills may be vastly sharpened by riding the same bike on your commute!