shacl validate exit code

### Version

4.7.0

### Feature

`shacl validate` currently returns 0 exit code even when there are violations. Can this be changed to 1?

### Are you interested in contributing a solution yourself?

Perhaps?

Start with the `shacl validate` command entry point and trace how validation results become the process exit code. Reproduce the 4.7.0 behavior with data containing violations, then verify that violations return 1 while a successful validation retains its existing exit code.

Written by the indexing model from the issue text.