sg: justify commands output on sg run/start

Created by: jhchabran

It's nicer to read right?

We could probably refine this, like detect what's the longest command name possible with the current set, but this was so quick to do that we'd rather get this shipped rn.

Test plan

Tested locally + checked manually what's the longest command we're running with

 cue eval --out=json sg.config.yaml | jq '.commands | keys'