Previously, when exports/ was missing or empty, the bash glob
`exports/*/` would not match anything and the loop would silently
do nothing. The job would pass without actually validating anything,
which was misleading.
Now the job:
- Explicitly checks if exports/ directory exists
- Uses nullglob to handle empty directories properly
- Logs clear messages when skipping validation
- Reports the number of agents validated when successful
Fixes#887
adionit7
e57cad7159