Describe the feature or problem you’d like to solve

Two separate issues, but both around the usability of the table printed by gh run list. The status indication and time-based sorting are helpful for finding runs, but can be difficult when there are many similar runs that kicked off around the same time.

Proposed solution

Adding column headers and an "age" column will help people more efficiently sift through their runs.

Additional context

It's a bit hard to know exactly what these column values are.

kubectl provides some good prior-art references here.