A peer-support program meant to help San Francisco firefighters and paramedics process the stresses of their jobs could see its first major expansion in nearly two decades. The program, often described as effective but lacking resources, is seen by many within the department as critical to helping first responders manage the lingering post-traumatic stresses that can accompany their often harrowing work. On Wednesday, the Fire Commission is set to vote on an initiative directing Fire Chief Joanne Hayes-White to spend the next few months researching how the department can begin training more peer counselors and creating a support network that can help first responders process the mental demands of the job.