Is It Possible to Achieve a Rounder, More Protruded Forehead?

It is not a good idea to have a hydroxyapatite implant placed in the forehead due to the numerous complications that have been reported in the literature and from my own personal experience. There are no other options for reshaping bony forehead. Consider a different hairstyle to cover the forehead.

Unless your forehead is really abnormal in appearance, I would not look to have it augmented in any way. Any graft material like hydroxylapatite may leave irregularities and be more of a problem than some flattening.

Cosmetic surgery of the forehead is usually done in several conditions. In men, when there is a prominent (supra orbital) ridge behind the brows (giving the person an especially over-masculine / cave man) appearance it could be burred down. When a forehead needs to be augmented it can be done with application of computer generated implants or by application of PMMA (polymethylmerthacrylate) and burring it down as needed.
These procedures are far from being complication free and may not be for you if you "don't want any complications."
Cosmetic surgery of the forehead is usually performed by Plastic / Craniofacial surgeons and San Francisco has several excellent ones. You should see several of them and learn what each has to say before proceeding.